Policy
Simulation
Group

Pension Projection Models

Enhancements Introduced in Earlier Versions of the PSG Models (since 2004)

2010-Jan
No enhancements.

2009-Dec
Fix a typo in PENSIM source code that prevented aggregation of threaded PENSIM output generated by multiple-scenario runs that specify .xsc output but not .xsd and .xse output. Thanks to Stan Panis of Advanced Analytical Consulting Group for reporting this bug. This fixes a bug that has been in PENSIM since April 2009 when the PENSIM .xsd and .xse output files were added. This change has no effect on the values of PENSIM output statistics.

Add PENSIM code that turns off the accessing of an individual's rollover account (for the purpose of making withdrawals or buying a life annuity) when that individual recovers from the disability that triggered the start of rollover-account accessing. This change eliminates a bug that has been in PENSIM since September 2007 when disability recovery was added to PENSIM. This change has small effects on pension benefits among the small group of individuals who recover from a spell of disability and who had a positive rollover-account balance during the spell of disability. For example, in the PENSIM run used to identify and fix this bug, only 56 out of 205,397 individuals (0.027 percent) were affected.

Add federal income tax saver's credit statistics to supplement 5 of the PENSIM cross-sectional surveys XSA, XSB, XSC, XSD, and XSE.

Add federal income tax logic to PENSIM that computes AGI and a refundable saver's credit structurally similar to that proposed in the FY2010 federal government budget. In the current version of the model, all the saver's credit is assumed to be deposited either in the individual's DC pension plan account or in the individual's pension rollover account.

Upgrade the Info-ZIP zip.exe utility included in the PSG models distribution from version 2.31 to version 3.00, and upgrade the unzip.exe utility from the 5.52 to the 6.00 version.

Add the individual's lifetime asset-allocation style to the PENSIM .cov output results file.

Improve PENSIM input database documentation for seven tables that are related to asset returns, especially returns on different corporate equity asset categories.

Add to the RSF Toolkit Execute menu a new item that provides access to the AWS Toolkit, which can be used to control the execution of runs on Amazon Web Services (AWS) computers.

Fix a minor logic bug in the calculation of survivor benefits for foreign-born individuals who emigrate from the United States after establishing their insured status and then die leaving a surviving spouse. This bug was introduced into the PSG models during 2008 when the migration logic of the models was revised extensively to reflect the change in migration methods used to produce estimates in the Trustees Report. This bug fix avoids a rare, but fatal, error in stochastic OLC runs and it causes a minuscule increase in average benefits. The increase in average benefits is so small that there is no change in the value of any of the OASDI solvency statistics in the .ssa output file for a standard deterministic OLC run. The incidence of the bug was so rare that none of the benchmark run results change after fixing the bug.

2009-Nov
Streamline logic of dbrun utility that is employed to "use" run specification files in the RSF Toolkit. This logic improvement produces a substantial speed up in the creation of model runs from rsf, with the "use" time dropping from five seconds to one second for a simple RCS mode run specification file employed in the testing of the enhancement.

Standardize the order of the model create-run sections produced by the RSF Toolkit "build" process. The order of the sections in all run modes is now PENSIM at the top, GEMINI in the middle, and SSASIM at the bottom of the run specification file. This change facilitates comparisons of the contents of two run specification files using the "Contrast two files on disk" item on the RSF menu of the RSF Toolkit. Run specification files that do not have this new section ordering can still be used by the RSF Toolkit.

2009-Oct
Revise extensively the automated install/upgrade procedure, primarily to make it easier to use by IT staff who are in charge of installing and upgrading the PSG models for users who do not have administrative privileges on their personal computers. Other enhancements to the install/upgrade procedure include: the suggested model installation folder is better aligned with the file structure in Windows Vista and Windows 7, the appropriate environment variables are set in a new way that works on Windows XP, Windows Vista, and Windows 7, and the prompt for the model installation folder has been eliminated when doing an upgrade.

Change the handling of directory naming in the PSG models so as to gain flexibility in locating the model installation folder within the Windows file structure. As users move from Windows XP to Windows 7, the Windows file structure strongly suggests installing the models in the \Users\{username} directory rather than in the root \ directory. This change will affect only those who use database directories other than the default db subdirectory. If you have done this, be sure to read the new documentation on the SSASIM OLC.gemini_dir, ESP.pensim_dir, RCS.gemini_dir fields, on the PENSIM RUN.ssasim_dir field, and on the GEMINI RUN.ssasim_dir, SAMPLE.pensim_dir fields. If you use only the default db subdirectories, there is nothing to do.

Change the default backup folder/directory in the RSF Toolkit so as to gain flexibility in where the backup file is stored within the Windows directory structure. The new backup folder/directory is the parent folder/directory of the SSASIM model installation folder/directory, but you can change that to be anything you want by changing preferences on the RSF Toolkit Help menu.

Upgrade gnuplot graphing program from version 4.0 to 4.2.6 so as to take advantage of bug fixes and new features that will be used by the analysis toolkits in the future. Add new png graphics format option to TFS Toolkit, the trust-fund solvency analysis toolkit. The png graphics format is lower quality than the existing eps or pdf graphics formats, but a png file can be viewed on the screen and printed without Adobe Acrobat Standard or Adobe Acrobat Professional being installed, and it can be inserted into a Microsoft (Word, Excel, PowerPoint) document without going through the hassle Microsoft has made out of importing eps files.

Upgrade database library to SQLite 3.6.19 release, which enforces foreign-key constraints. Revise SQL statements that define the PSG model input database tables so that referential integrity is enforced with triggers rather than with foreign-key constraints, which were parsed but not enforced in earlier SQLite releases. These changes are extensive, but should not be visible to users of the PSG models.

Add INCTAX table, and several INCTAX child tables, to the PENSIM input database. These tables will contain federal income tax policy parameters for years beginning with 2004. Adding a federal income tax capability to PENSIM is a major undertaking that will involve months of work. In the meantime, there will be signs of the construction effort and users should not attempt to set the value of PENSIM RUN.use_inctax to true.

2009-Sep
Add two new fields to SSASIM PRDMRKT table that enable the simulation of a one-time perturbation to the annual inflation rate followed by an offsetting perturbation in the following year.

Add the ability to simulate a payable-benefits policy in stochastic runs, which replaces the old BEND_DI.pay_pct and BEND_RI.pay_pct fields that worked only for deterministic (single-scenario) runs. This new ability is implemented by adding a field to SSASIM RUN table that specifies an optional input file that contains OASI and DI payable-benefits percentages for each year of each scenario. This new field, RUN.paypctfile, contains a single dot character in all the benchmark runs that are used as base runs in run specification files, implying a scheduled-benefits policy. A payable-benefits policy can be implied by specifying the name of a file that has the same format as the new .pay output results file (see next item). See the SSASIM input database documentation for details on the new RUN.paypctfile field and the two simple steps required to translate a .pay output file into a paypct input file.

Add a new output results file to SSASIM that automatically generates payable-benefits percentages for each scenario year. The new .pay output file contains payable-benefits percents for the OASI and DI programs, separately, for each year of each scenario. See the SSASIM input database documentation for details on the two new fields: OUTPUT.pay and OUTPUT.pay_preyrs.

Add a suite of tests that checks for identical output in stochastic runs in all modes of operation regardless of which threading or distributed-processing options are used. Threading of cohort samples in OLC runs has been a feature of the PSG models since 2003, and threading of scenarios in stochastic ESP and RCS runs was added in March 2009. Distributed processing of bundles of scenarios in stochastic ESP, RCS, and OLC runs was added in July 2009. Threading utilizes multiple cores in a single computer, while distributed processing utilizes several computers on a network. The new test suite ensures that runs produce exactly the same results no matter what combination of threading and distributed processing is specified.

Add the ability to edit, in the RSF Toolkit editor, files used as or with post-simulation tab scripts. The three types of files are Windows batch scripts (*.bat files), Tcl programs (*.tcl files), and AWK programs (*.awk files). The RSF editor can now use the full range of editing commands on these three file types. This enhancement allows the preparation in the RSF Toolkit editor of files used as or with tab scripts. See the description of the RUN.tab_script field in the SSASIM input database documentation for details on how to automate post-simulation analysis of the raw output files generated by the PSG models.

Add a new PENSIM table that contains pension account fees for rollover accounts and for automatic-IRA accounts. The new table, which is a child of the PENSIM RUN table, is called ACCTFEE. See the documentation of the ACCTFEE for details on account fees, which are indexed for price inflation. The baseline values of both fees have been set to zero in order to replicate the

2009-Aug
No enhancements.

2009-Jul
Add three new fields to the SSASIM RUN table that together create an optional ability to split multiple-scenario runs into subruns, each one of which simulates a bundle of scenarios that is a subset of the total number of scenarios in the run. The purpose of this new capability is to support distributed processing of subruns on separate computers, with the subrun output results being merged after all the subruns have finished execution. The merged output results are the same as would be produced by the original run if it was not split into subruns. The point of the distributed processing is to execute a very long stochastic model run in less time than it would take to execute on a single computer. For example, using five identical computers to distribute the processing means that five subruns can be executed in about one-fifth the time required for sequential execution of the subruns on one computer. And, if even more computers are used for the distributed processing, the execution time can be reduced dramatically. The three new SSASIM RUN table fields are called dp_active, dp_f_scen (the first scenario in the subrun's bundle), and dp_l_scen (the last scenario in the subrun's bundle), and they are described in the new SSASIM input database documentation. RUN.dp_active is set to false in all the benchmark runs, which means that no changes need to be made in old run specification files in order to continue using the PSG models in the conventional non-distributed-processing way.

Develop two utilities that support distributed processing by automating the tasks of splitting a multiple-scenario run into subruns and merging output from all the subruns. The PSG models distributed-processing capability is a simple application of the Google MapReduce framework. The dp-split utility (the Map step) creates many subrun specification files from the original stochastic rsf. The dp-merge utility (the Reduce step) combines the output from each subrun into a single set of output results files that is equivalent to what would be produced by executing the original rsf. The utilities are short Tcl programs named dp-split.tcl and dp-merge.tcl that are invoked by the dp-split.bat and dp-merge.bat scripts, respectively. All four of these dp-* files are located in the SSASIM executables folder, where they can be read to understand how they work. They can be used in a wide variety of distributed-processing environments, including the distribute processing of subruns on a local area network of computers running the PSG models.

Remove the four lines at the bottom of most SSASIM output files that repeated the header line and showed the mean, standard deviation, and standard error of each output statistic. Revise the logic of all the res output tabulation utilities to handle the new file format.

Remove all-scenario summary lines at the bottom of the PENSIM .arc output file and at the bottom of the GEMINI .arc output file. Revise documentation of these two output files to include instructions for how to compute all-scenario solvency of the annuity provider in multiple-scenario stochastic runs.

Upgrade the Tcl language interpreter used by the PSG models from version 8.5.2 to the first 8.6 beta version.

Correct values for the low-benefit threshold in the SSASIM COHORT table rows used by the 2008TR benchmark runs and by the 2009TR benchmark runs, so that their values correspond to what the COHORT.notes field says they are: Census Bureau poverty lines. PSG model users can set these low-benefit thresholds to any values they want.

Add a new field to each of the SSASIM trust FUND tables. The new field is called firstchkyr and it specifies the first calendar year in which a check is conducted for a relatively flat maturity profile for special-issue Treasury bonds held in the trust fund. This check is conducted only if sprd_mats is true and rmv_by_cpn is false, which are the default values in all the benchmark runs. If the check finds a maturity profile that is not very flat, a warning message (that includes all the special-issue Treasury bonds held by the fund) is printed and run execution continues. If, after studying such a warning message, you are certain everything is being simulated as you want, you can suppress the warning message by setting this field to a year after the last printed warning message. These new fields have been added to replace hard-coded first check years, and therefore, they add flexibility for model users, but do not represent any new substantive capabilities in the PSG models.

Add new field to PENSIM TRACE table that is named coh_b_year. The logic associated with this new field makes it possible to trace an individual or spouse included in a cohort sample born in a specified year during an OLC run.

Change PENSIM asset terminology so that 'life-cycle fund' becomes 'target-date fund' to keep up with English usage trends. This is a change in terminology only; no changes have been made to model logic. All model documentation has been revised to reflect this change. Old run specification files that include the lcf_pct_f or lcf_pct_m fields in any one of the four ACCTAA1-ACCTAA4 tables need to be changed to work with the new version of the PSG models. Simply change every lcf_pct_? to tdf_pct_? in each rsf that you want to use with the new version of PENSIM.

Add two new fields to the PENSIM PENBEHV table that specify a separate stream of random numbers that are used to simulate individual pension behavior related to auto-IRA plans. The number of auto-IRA random numbers drawn for each individual lifetime, PENBEHV.num_aiu, has a value of one in the benchmark runs that do not assume any auto-IRA plans, so when simulating an auto-IRA reform be sure to increase this number above one.

Add a new field to the PENSIM CSTOCK table that specifies whether or not the random number streams that are used to simulate company-stock returns are synchronized across runs that have the same number of sample individuals and job histories. The new field, which is called CSTOCK.sync_rns, is set to false in the benchmark runs. When setting it to true expect at least a ten percent increase in PENSIM run execution times.

2009-Jun
Add four existing PENSIM migration tables (EMIGRA, EMIGDYN, IMMIGRA, IMMIDYN) to the scope of the run specification language and add documentation for all parameters in those four tables.

2009-May
Add five new benchmark runs that use the intermediate-cost assumptions from the 2009 Trustees Report. The new runs are as follows: CBA 19, OLC 39, ESP 59, RCS 79, and ESP+ 99. Given that pension benefits need to be computed in order to calculate social security benefits correctly (given the existence of the WEP/GPO benefit reduction rules that are part of current-law policy), both the OLC solvency run 39 and the RCS distributional run 79 use PENSIM to compute employer-sponsored pension benefits, which are then used by GEMINI to compute social security benefits. The Build process in the RSF Toolkit has been revised to use these 2009 benchmark runs as the base runs when specifying a new run. A one-in-a-thousand-sample-size OLC run, using run 39 as its base, produces OASI, DI, and OASDI summarized cost rates, summarized income rates, and actuarial balances, that are the same (within rounding error) as those shown in the 2009 Trustees Report for the intermediate-cost assumptions.

Add six new fields to the SSASIM POP table that together determine foreign-born emigration rates that vary by years since immigration and by age. The resulting foreign-born emigration rates are used to implement (in CBA mode runs only) the explicit-emigration logic that was introduced in the 2008 Trustees Report. The new migration logic has been used in all other modes of PSG model operation for almost a year. Now all PSG model runs use the new explicit-emigration logic, which is described in the 2008 Trustees Report on pages 76 through 81. The new migration logic will be activated beginning with CBA mode benchmark run 19, which will incorporate 2009 Trustees Report intermediate-cost assumptions. CBA mode benchmark runs that use assumptions from Trustees Reports dated before 2009 continue to use the old migration logic.

Remove the SSASIM reform option to have the social security COLA be computed using the average wage index (AWI) instead of the consumer price index (CPI).

Add logic to the indexing rules for MTE, XTE, and ETE amounts (see the SSASIM MTE table) that suspends the indexing in years for which the (pre-offset) social security benefit COLA is zero.

Upgrade the SQLite programs and source code that are part of the PSG models to the 3.6.14.2 version.

2009-Apr
Add two new cross-sectional surveys to PENSIM output, which brings the total number of cross-sectional surveys that can be conducted in a single run to five.

Add to SSASIM the capability of executing, at the very end of a run of the PSG models, any specified script that tabulates raw output generated by that run. This enhancement provides a convenient way to automate the processing of a run's raw output so that any kind of post-simulation analysis or storage of the raw output files can be conducted. The script can be either a Windows batch file or a Tcl program. This enhancement requires the addition of a new field at the end of the SSASIM RUN table called tab_script.

Upgrade the SQLite programs and source code that are part of the PSG models to the 3.6.12 version. There should be no visible change in the operation of the PSG models because of this change.

2009-Mar
Implement a series of changes that together create a threading capability for stochastic ESP mode and RCS mode runs. This threading capability allows these kinds of runs to make use of all the CPU cores present on a computer, and therefore, to execute much faster.

Alter slightly the way in which inflation rates are computed for years since 1997 and the way they are used to calculate the social security COLA. These improvements cause very small changes in social security results (in CBA, OLC, and RCS modes) that are of no policy significance and cause very small changes to inflation-adjusted pension benefits (in EPS and ESP+ modes).

2009-Feb
No enhancements.

2009-Jan
Add eight new statistics at the end of the GEMINI .sum output results file that are money's worth (present value and real internal rate of return) statistics for account-based employer-sponsored pension plans. Consult the revised documentation of the GEMINI .sum output results file for the definitions of the new pension statistics, which are numbered from (45) to (52). The new statistics are computed using pension benefits and pension contributions (from both employees and employers) for all DB/CA (cash balance) and all DC plans over the cohort individual's lifetime. Note that all traditional DB plans are excluded from the calculations.

Add to PENSIM the ability to simulate automatic-IRA pension plans, like those proposed in J. Mark Iwry and David C. John, "Pursuing Universal Retirement Security Through Automatic IRAs: Executive Summary," The Retirement Security Project, April 2007. The automatic-IRA plans have been added as a new fifth type of DC pension plan. This enhancement involves the addition of four new PENSIM input database tables containing the offering requirements and characteristics of automatic-IRA plans, and the addition of new fields in the LAW_CYR policy table to indicate the timing of the automatic-IRA reform and the inflation-indexed level of the maximum IRA contribution amount. Several PENSIM output files have been changed to report the new DC plan type. In addition, several PENSIM enhancements add new pension behavior parameters to allow assumed behavior of automatic-IRA eligibles to differ from that of other DC-plan eligibles.

Expand scope of cross-sectional-survey supplement 3, which is an option in the PENSIM .xsa, .xsb, and .xsc output results files. This supplement now reports information on prior-year rollover decisions associated with all types of DC plans (including automatic-IRA plans) rather than just DC/ST plans.

Add four new pension characteristic parameters for zero-matching DC/ST plans. The new parameters permit the zero-matching DC/ST plans to have automatic-enrollment arrangements or not. The four new parameters are located in the ZMPDBP1, ZMPNOP1, ZMPDBG1, and ZMPNOG1 tables, which correspond to the setting within which the employer offers the zero-matching DC/ST plan. The benchmark runs set the value of these new parameters to false, which has been the hard-wired value since the zero-matching DC/ST plans were added to PENSIM in 2007. When the zero-matching DC/ST plans do have automatic enrollment, the default contribution rate is always three percent and the default investment is always the target-date fund.

Revise the 2008 pension law parameters used in PENSIM benchmark runs. Previous versions of PENSIM used published pension limitation amounts through 2006 and then inflation indexed the 2006 amounts in subsequent years. The new version of PENSIM uses published pension limitation amounts through 2008 and then inflation indexes the 2008 amounts in subsequent years. This enhancement creates some very minor differences in the benchmark run results.

Add the ability to simulate government contributions to DC/ST plans, including the so-called zero-matching DC/ST plans. The government contributions can be either a flat annual amount or a fraction of employee contributions up to an annual limit or a combination of the two (that is, a contribution that has a flat component and a matching component). The policy parameters that specify the nature of the government DC/ST contributions are in a new PENSIM table, GPC_CYR, which is a child table of PENLAW. In conjunction with these new policy options, the PACONT1 table now contains a new employee contribution behavior parameter (gpc_f_o_r) that specifies the rate at which employee contributions are reduced when the government offers a flat contribution. Also, add output statistics related to the new government pension contributions (GPC) to both the PENSIM .cst cost output file and to supplement 1 of the .xsa, .xsb, and .xsc output files. Read the documentation of those output files to get the details of the GPC statistics.

Add two new payroll tax rate parameters and rename one payroll tax rate parameter in both the SSASIM TAXR_DI table (for DI tax rates) and the SSASIM TAXR_RI table (for OASI tax rates). These changes allow the specification of a payroll tax rate that differs across two age groups. The boundary age between the two groups and the payroll tax rates that apply to the two age groups can vary from year to year. Consult the revised documentation of the SSASIM input database tables TAXR_DI and TAXR_RI for details.

Add a new kind of fund to the list of assets in PENSIM, which involves adding two new fields to the ASSETS table and two new fields to each of the four ACCTAAn (account-asset-allocation) tables. The new so-called guaranteed-return fund is somehow engineered to provide a constant real (i.e., adjusted for inflation) rate of return every year. The two new ASSET table fields allow specification of the assumed real rate of return and the fund's fee. And the two new ACCTAAn table fields allow the specification of gender-specific and age-specific portfolio percentages for the guaranteed-return fund that apply to all DC plan accounts as well as to all rollover accounts. There is no attempt in the current version of PENSIM to estimate the cost to the fund of providing such a guaranteed real return. If the guaranteed return is low relative to returns on market assets, then the fund could probably make a long-term profit providing the guaranteed real return. On the other hand, if the guaranteed return is high relative to returns on market assets, then the fund would be likely to incur a long-term loss providing the guaranteed real return. The current version of PENSIM does not estimate the highest level of guaranteed real return that avoids a long-term loss for the fund.

Revise the PENSIM PAINVS table parameters having to do with default investment endorsement effects to allow different endorsement effects in defined-contribution savings-thrift (DC/ST) plans and in automatic-IRA (DC/AI) plans.

Remove the PENSIM PAROLL1 table full_ai_ro field and add the PAROLL2 table is_ai_plan field, which is a binary logit equation coefficient for a dummy variable that is one only when the individual at job end has a positive balance in an automatic-IRA (DC/AI) pension plan. The addition of this parameter allows the rollover behavior of DC/AI participants to differ from that of other DC plan participants.

Upgrade the SQLite database library and utility programs from version 3.6.0 to version 3.6.10, which should have no visible effect on PSG model operations or results.

2008-Dec
No enhancements.

2008-Nov
Add quarters-of-coverage statistic to GEMINI .sum and .bAA output files.

2008-Oct
Add docage, which is statistic (43) in the GEMINI .sum output file, to the end of each row of the GEMINI .bAA output file, where it becomes statistic (30). Add the percentage annual rate of return on trust-fund assets to the end of each row in the SSASIM .dfc, .dfd, and .dfr output files as statistic (14). Make several minor revisions to the source code that cause very small changes in some output statistics, typically in the fourth or fifth digit. These code changes should cause no substantive change in output from the PSG models.

2008-Sep
Enhance the GEMINI trace capability so that any individual, either cohort sample members (with positive id values) or spouses of sample members (with negative id values), can have detailed annual tracing information written out during either RCS or OLC mode runs. Add two new statistics to the I row of the PENSIM .pen output file, which changes the column numbers of the first-age and last-age statistics at the end of the I row in the .pen output file. Add two new migration-related statistics to the core questionnaire of the GEMINI .xsa, .xsb, and .xsc output files, which changes the column numbers of most of the output statistics in these files. Add one new migration-related statistic at the end the GEMINI .sum output file. Change the value of GEMINI .sum statistic 36 (age at which initial OASDI benefit is received) when no benefit is ever received: the no-benefit age was -1 in prior versions; now the no-benefit age is 999.

Prepare new benchmark runs that incorporate intermediate-cost assumptions and methods from the 2008 Trustees Report. The new Trustees Report projection includes substantial changes in migration assumptions and methods, which account for a sizable improvement in the OASDI actuarial balance. The new benchmark runs distributed with this version of the PSG models simulate migration so that the both annual-total and age-specific counts for both net and gross immigration are close to those in the Trustees Report projection. The migration logic of the PSG models is somewhat different than that of the Trustees Report projection, and the CBO CBOLT model, in three ways:

(a) The logic has been modified so that some immigrants lack sufficient documentation to claim social security benefits, even though they have paid social security taxes when they work in the United States. This enhancement enables the PSG models to simulate, at the micro level, the so-called earnings suspense file, which accounts for trust-fund revenues that cannot be matched to a valid social security number and which constitutes a substantial fraction of the total trust-fund balance. Both OCACT and CBO are assuming in their projections that in each year about 1.3 percent of OASDI payroll tax revenue flows into the suspense file, which is also what the new PSG-model benchmark runs assume. Unlike the other models, the immigrants who contribute the 1.3 percent of taxes are included in the mainstream simulation, but receive no OASDI benefits because of their undocumented status.

(b) Another difference between OCACT (but not CBOLT) and the PSG models is the assumption that the distribution of educational attainment (and hence, earnings) among immigrants differs from that of the native born, with immigrants having somewhat higher proportions of both low and high educational attainment.

(c) The final difference is that the new logic of higher gross immigration and emigration flows begins (as in the real world) decades ago in the PSG models rather than beginning more recently at the start of the simulation period. This happens in the PSG models because all cohorts born since 1935 are simulated from life to death. The implication of this difference is that the composition of new retirees is being affected by the higher assumed migration flows sooner in the simulation period.

Activate the recently-developed WEP/GPO benefit reduction rules in the new benchmark runs that use 2008 Trustees Report assumptions. The pre-2008 benchmark runs continue to not simulate the WEP/GPO rules.

The new migration methods and assumptions, together with the activation of the WEP/GPO benefit reduction rules, cause a widening in the long-standing gap between the OASDI actuarial balance estimated by the PSG models using standard microsimulation methods and the estimate in the Trustees Report. The 2004 gap was 54 basis points (-1.35 versus -1.89, with CBO reporting a CBOLT estimate of -1.36 for that year using Trustees Report assumptions); the 2007 gap was 38 basis points (-1.57 versus -1.95 percent); the 2008 gap is 72 basis points (-0.98 versus -1.70 percent). As a result, the size of the annual actuarial adjustment factor needed to emulate OCACT methods has grown. The new factor values are used in the RSF Toolkit Build process when choosing the emulate OCACT methods option and when the Trustees Report year is 2008. The PSG models still produce the 38 basis point gap when ignoring the WEP/GPO benefit reduction rules and using the old migration assumptions and methods from the 2007 Trustees Report. Note that, as in past years, the PSG model projection using 2008 Trustees Report assumptions closely matches the projections of population, taxable earnings, DI revenue, DI cost, OASI revenue, and OASI beneficiaries in the 2008 Trustees Report. The sole projection difference, as in past years and as found in other microsimulation models, is that projected average OASI benefits for the baby-boom cohorts are lower than in the Trustees Report. If the lifetime earnings of those cohorts were to be assumed to be high enough to generate the average benefit levels projected in the Trustees Report, it would be impossible to match the taxable earnings projection in the Trustees Report and the current balance of the trust funds would be much larger than they are in reality. In other words, the logic of the microsimulation method, which requires that the same lifetime earnings be used to estimate both payroll tax revenues and benefit costs, makes it impossible to match all aspects of the Trustees Report projection.

The new migration methods and assumptions, together with the activation of the WEP/GPO benefit reduction rules, cause a substantial increase in the execution time of OLC and RCS mode runs. This increase in run execution time is caused by the fact that many more migrants are being simulated in a run and because employer-sponsored pension benefits now need to be simulated in order to accurately compute OASDI benefits using the WEP/GPO rules. On a computer that executes a 0.1 sample_pct OLC run using old assumptions and methods in about 1.9 minutes, now takes about 5.3 minutes to execute the same run using new assumptions and methods. In coming months, we hope to be able to develop an imputation scheme that will approximate uncovered pension benefits without running PENSIM in full-pension mode. If we are successful, OLC mode run times should be cut roughly in half.

The RSF Toolkit preferences file has been changed so that the new 2008 Trustees Report benchmark runs are used as the base runs when a run specification file is built by the Toolkit. If you have changed other settings in the preference file, be sure to save those settings so that you can enter them after doing the upgrade. If you want the RSF Toolkit to use the 2007 Trustees Report benchmark runs as the base runs in an rsf (as done in prior versions of the models), simply edit the preferences file using the RSF Toolkit Help menu item called "Changing toolkit preferences."

Revise the pension offering assumptions in PENSIM so that the base ESP mode run 58 assume that the prevalence of automatic-enrollment in private-sector DC/ST plans rises from zero to seventy percent over the 1998-2012 period. This is the baseline assumption for the new 2008 benchmark runs, but alternative assumptions can be easily specified using the run specifications language.

2008-Aug
No enhancements.

2008-Jul
Add an extra year of life before accelerated mortality starts in PENSIM runs that support SSASIM OLC mode runs. Add a pension excise tax as a policy option in the PENSIM LAW_CYR table, with the revenue of this tax on employer-sponsored pension distributions being deposited in the OASI trust fund. Add individual behavior parameters to PENSIM PAROLL1 table that can be used to eliminate completely pension account rollovers at job-end. Add two statistics to the PENSIM .cov output file that report the number of lifetime jobs on which an individual vests in a DB (DC) pension plan on a job where that individual's earnings are not subject to social security payroll taxes. Upgrade the PSG models to SQLite 3.6.0 version and to GNU AWK 3.1.6 version. Add SSASIM constraint that the values of pia_frac_1 (the PIA-formula fraction that applies to AIME amounts below the first bend point) in the PIADYNR, PIADYNS, PIADYND tables must be the same.

2008-Jun
Move GEMINI .xsa output file statistic (22) from the supplementary to the core survey questions. Add GEMINI .xsb and .xsc output files that have the same file layout as the .xsa output file. Add field scnsid_ind to STATS table in GEMINI input database with the new logical field controlling whether individual or adult-equivalent-couple benefits and earnings statistics are used to construct the statistics included in the GEMINI .scn and .sid output files. Change GEMINI input database parameter values used in the adult equivalents formula in the RCS mode and ESP+ mode benchmark runs in order to make statistic (41) in the GEMINI .sum output file a more conventional denominator in retirement income replacement rates. Add SSASIM .pfp output file, which contains annual values of PIA formula parameters: the three bendpoints and four formula percents for each of the three eligibility events. Add three certainty-equivalent statistics to GEMINI .sid output file and three certainty-equivalent statistics to GEMINI .scn output file. Add sid_crra field to STATS table in GEMINI input database for specifying the constant relative risk aversion (CRRA) parameter in the expected utility function used to calculate the new certainty-equivalent statistics. Add a new field to both the BEND_DI and BEND_RI tables that allows a change in the method of computing DI and OASI COLAs. Prior model versions always computed annual COLAs using a CPI-indexing method, but now there is the option to use an AWI-indexing method.

2008-May
Revise the source code of the PSG models so that the core models and utilities — but not the various Toolkits — can compile and execute under operating systems other than Windows. So far, this has been done successfully for Mac OS X (10.4+) and Debian 4.0 (32-bit) Linux. The purpose of this work is to gain access to more powerful hardware platforms such as the Mac Pro, which has eight Intel Xeon cores standard, and cloud computing facilities that offer scores of quad-core Linux servers for rent by the hour. Upgrade the Tcl interpreter included with the PSG models to Tcl 8.5.2 version. Upgrade the PSG models to SQLite 3.5.9 version. Add SSASIM INSURED table that includes the main policy parameter that determines whether an individual is "fully insured" for OASDI benefits. Provide a PENSIM xsall utility that automatically combines the many xs?NNNNN.YYY files produced during an OLC mode run into a single xs?NNNNN.all file that represents a genuine cross-sectional sample of individuals drawn at the survey moment during the survey year. Add to PENSIM the ability to trace the life events experienced by a spouse of a sample individual. Add to PENSIM pension behavior the possibility that individuals cashout the lumpsum equivalent of their vested benefits in career-earnings or terminal-earnings defined-benefit plans when the job ends before retirement, disability, or death. Add GEMINI .sid output file that contains information on each sample individual used to tabulate the scenario statistics contained in the .scn output file, which allows calculation of statistics that measure the variability of social security and pension benefits (a) across stochastic scenarios, (b) across cohort individuals within each scenario, and (c) across retirement years for each individual.

2008-Apr
Add an embedded-SQL capability to the RSF Toolkit's run specification language, which means that now all parameters in the input databases of the PSG models can be manipulated using the run specification language without having to work directly with the databases. Add PENSIM .mig output file that contains aggregate migration and population counts for the simulated birth cohort. Revise PENSIM schooling logic and tables so that native-born and foreign-born individuals can have different educational attainment distributions. Revise the GEMINI AAAF parameter so that it can be a negative number.

2008-Mar
Add ability to specify exemplary cohort individuals (ECI) using the RSF Toolkit's run specification language. Add to SSASIM input database "scaled earnings" profiles derived by OCACT from 2007 Trustees Report assumptions. Add PENSIM cross-sectional survey supplement 7 that contains statistics that can be used to determine how many individuals work beyond the age at which they are eligible for unreduced (or normal) benefits from the defined-benefit plan covering them on their current job; the new supplement to the PENSIM .xsa, .xsb, .xsc output files has been used by DOL/EBSA in a regulatory impact analysis.

2008-Feb
Revise the baseline PENSIM assumptions concerning the transition probabilities between the positive-annual-contribution state and the zero-annual-contribution state using MINT5 estimation results. Add PENSIM DBWITH1 table parameters to determine gender-specific probabilities of a married individual choosing a single-life annuity as the payout from a traditional defined-benefit pension plan (rather than the default, under federal law, joint-and-survivor payout); the new parameters are set to produce probabilities tabulated from 1992-2000 HRS data shown in the MINT5 final report. Add four earnings statistics to the GEMINI .xsa output file.

2008-Jan
Provide a free educational version of GEMINI and add the ESP+ mode benchmark run to the RSF Toolkit. Add ability to define a range of earnings that is excluded from OASDI taxable earnings, allowing specification of so-called "donut-hole" payroll tax reform provisions.

2007-Dec
Add to EDA Toolkit a page containing the numerical value of statistics that appear in the graph; make several other improvements in the EDA Toolkit.

2007-Nov
Add immigration and emigration ages to PENSIM .cov output file. Upgrade the PSG models to SQLite 3.5.2 version.

2007-Oct
No enhancements.

2007-Sep
Add disabled adult children to the PSG models. Add recovery from disability as a life event in PENSIM. Add zero-employer-matching savings-thrift plans to PENSIM using custom tabulations of 1996-97 private-sector and 1998 public-sector Employee Benefit Survey data performed by BLS staff at the request of EBSA. Add to GEMINI cross-sectional output files (.xsa, .xsb, .xsc) new supplements that contain information about beneficiary head counts using SSA beneficiary type definitions. Perform a cross-model validation test comparing beneficiary counts by benefit type in 2060 with estimates for 2060 in the Trustees Report, the results of which show that the PSG models produce estimates that are close to those of OCACT (except in the case of adult SI beneficiaries where the OCACT estimates seem too high given the upward trend in female labor force participation rates).

2007-Aug
No enhancements.

2007-Jul
Add to PENSIM cross-sectional output files (.xsa, .xsb, .xsc) a set of supplementary questions that produce statistics that can be compared to SCF data on defined-contribution balances. Begin adding logic and output statistics for zero-employer-matching savings-thrift plans, which are soon to be introduced into PENSIM. Improve the realism of the Markov process that determines annual transition probabilities in to and out of the state of defined-contribution participants making a zero annual contribution. Calibrate employer probabilities of offering different types of pension plans over the 1975-2005 period using publicly available data. Conduct two validation tests of PENSIM estimates of defined-contribution account balances using 2004 SCF data and 2005 data from the EBRI-ICI 401(k) database, and describe the validation test results in the PENSIM Overview.

2007-Jun
Provide a run specification file for a CBA mode run that produces stochastic results similar to those in the 2007 Trustees Report. Upgrade the PSG models to SQLite 3.4.0 version. Revise the effect of PENSIM INDBEHX retirement delay so that nobody delays retirement beyond age seventy. Add three sets of supplementary questions to core survey questions in the GEMINI .xsa output file.

2007-May
Add new PSG models benchmark runs that use 2007 Trustees Report intermediate-cost assumptions. Change the compiler collection used to build the PSG models from Open Watcom to GNU running under MinGW; the resulting models are slightly larger, but run noticeably faster: one-thousand scenario CBA mode runs are roughly the same speed, OLC mode runs are about twenty-five percent faster, and RCS mode runs are almost thirty percent faster. Add a supplement 5 to the three PENSIM cross-sectional survey output files (.xsa, .xsb, .xsc) that is a March-CPS-style prior-year-retrospective survey on annual earnings and annuity transactions. Add to PENSIM an exemplary cohort individual account saving feature that simulates account contributions, returns, and balance for a single individual, allowing PENSIM to generate simple projections of one individual for comparison with results from other studies (see, for example, the wildly misleading results in the CRS report by P. Purcell and D. Whitman, "Retirement Savings: How Much Will Workers Have When They Retire?" January 2007). Revise the GEMINI AAAF feature so that the annual actuarial adjustment factor can vary in value across calendar years. Add GEMINI .xsa output file that can be used to generate multiple-cohort cross-sectional survey output for a specified calendar year when GEMINI is operating in OLC mode.

2007-Apr
Change the database technology used by each PSG model so that the hundreds of Microsoft FoxPro files are replaced with a single-file SQLite database. Provide as part of the PSG models installation a Tcl language interpreter (tclkitsh.exe) as well as a Tcl SQLite dynamic link library (tclsqlite3.dll) so that any user can directly manipulate the model databases if the RSF Toolkit run specification language is not sufficient. Add a backup button to the RSF Toolkit. Add social security COLA offset reform to the list of reform provisions available in the RSF Toolkit Build interview. Add a tkprefs file that allows users to specify preferences about the Toolkits: the folder where backups are placed, the Trustees Report year, and the size of the Toolkit window and fonts. Add to PENSIM .pen output file a statistic that reports the couple's end-of-the-year rollover account balance. Add to the PENSIM .cov output file four statistics that report the number of years the individual held full-time jobs, held part-time jobs, was eligible for a defined-benefit pension plan, and was eligible for a defined-contribution pension plan. Add PENSIM INDBEHX table that contains individual behavior parameters are in the scope of the RSF Toolkit run specification language.

2007-Mar
Add to SSASIM AIME table five policy parameters that allow the specification of social security caregiver credit reforms. Add to the RSF Toolkit several new convenience features: multiple run specification file use, find and replace in all run specification files, and renaming of run specification files. Add to PENSIM cross-sectional survey output file a fourth optional supplement that focuses on pension eligibility and vesting a recent job endings. Add to the PENSIM DBVEST table four new parameters that allow the specification of maximum cliff vesting years across all defined-benefit pension plans, with the maximum possibly being different in the private and public sectors and/or possibly being implemented in different years. Add to the PENSIM DCVEST table four new parameters that allow the specification of maximum years to cliff vesting and maximum years to full graded vesting across all defined-contribution pension plans, with the maximum possibly being implemented in different years. Add PENSIM .age output file that contains selected individual statistics at each age in a specified age range. Add to the PENSIM .cov output file several statistics describing the longest job held by the individual. Add to PENSIM ASSETS table a so-called stable-value fund, revise the pension account asset-allocation (ACCTAA?) tables to allow investment in stable-value funds, and revise the cross-sectional survey output to include holdings of stable-value funds. Add to the PENSIM STAENR1 table an additional parameter having to do with automatic enrollment in defined-contribution pension plans. Add to PENSIM PAINVS table new parameters that allow the characterization of an "endorsement effect" caused by the selection of a default investment under automatic enrollment. Fix a bug in the out2bage utility inadvertently introduced by the source code changes made during February 2007.

2007-Feb
Add SSASIM and GEMINI trace output that confirms that negative PIA reductions at DI-to-OAI conversion are not applied in reforms that would appear to call for such reductions; this substantive change in logic was implemented in January of 2007. Extensively revise the source code of the PSG models to make the code more like C and less like C++, particularly with regard to string formatting and file reading and writing; the source code continues to use fundamental C++ features such as classes, templates, and inheritance. Add roughly two hundred tables in the PENSIM input database to the scope of the RSF Toolkit run specification language. Add the GEMINI TRACE table to the scope of the RSF Toolkit run specification language.

2007-Jan
Provide for the first time to the public a full-featured version of PENSIM that can simulate employer-sponsored pension accumulation and withdrawal. Revise the logic used to compute the maximum taxable earnings (MTE) level from the average wage index (AWI) so that it mimics more closely the actual administrative calculation.

2006-Dec
Revise the TFS Toolkit so that annual values of the income and cost rate are connected by lines if they are drawn from an actual scenario (rather than representing percentile values, which typically come from different scenarios each year). Provide a resce utility that computes the certainty-equivalent value of the distribution of an output statistic using either expected utility theory or cumulative prospect theory. Add to PENSIM a third cross-sectional survey, so that now up to three different cross-sectional surveys can be conducted in a single ESP mode run.

2006-Nov
Add to the RSF Toolkit Build interview the option of specifying an employer-sponsored pension (ESP) mode run, in anticipation of the public distribution of a pension-simulating version of PENSIM. Provide a Trust-Fund Solvency (TFS) Toolkit that produces a one-page summary that contains several solvency statistics and a time-series graph that shows income and cost rates in either deterministic or stochastic CBA mode or OLC mode runs. Add longevity indexing of the minimum PIA base amount in the SSASIM MINPIA table. Add to PENSIM a second cross-sectional survey, so that now up to two different cross-sectional surveys can be conducted in a single ESP mode run.

2006-Oct
No enhancements.

2006-Sep
Add to the RSF Toolkit the ability to see input database table values used by the base run by clicking a run specification language statement for a table with the right mouse button. Streamline the specification of spouses and kids in ECI mode runs and revise the ECI Toolkit to work with the new structure of the SSASIM input database tables. Add equity return and Treasury bill spread to the set of key SSASIM assumption variables, revise the run specification language to handle the new assumption variables, and revise several SSASIM output files to report their annual values. Add ability to make a one-time change in the wage-indexed level of minimum earnings required to earn a social security quarter of coverage. Add several PENSIM input database tables that allow more detailed specification of assets that can be held in pension accounts.

2006-Aug
No enhancements.

2006-Jul
Revise the RSF Toolkit in several ways and make it the standard interface to the PSG models. Provide an Exemplary Cohort Individual (ECI) Toolkit that automates extraction of output statistics to an Excel spreadsheet. Add a new employer-sponsored pension (ESP) mode of operation to the PSG models in anticipation of the public release of a pension-simulating version of PENSIM. Add to the EDA Toolkit the ability to create two-dimensional color histogram graphs that visualize the joint distribution of two continuous GEMINI output statistics.

2006-Jun
Provide a run specification file for a CBA mode run that produces stochastic results similar to those in the 2006 Trustees Report. Provide an Exploratory Data Analysis (EDA) Toolkit for tabulating and graphing statistics from GEMINI output files. Add GEMINI .cpi output file containing annual values of the CPI index. Revise the out2bage utility used by the EDA Toolkit to generate .bAA output files so that it uses the .cpi output file to convert nominal dollar amounts into real dollar amounts. Add to GEMINI .sum output file two "level earnings" statistics that are suitable denominators for individual and couple replacement rates.

2006-May
Update SSASIM HISTORY and HISTMDR tables with statistics for recent years and add new HISTMR table, so that now the last historical year in PSG model simulations is 2004 instead of 1997. Provide a run specification file for a CBA mode run that produces stochastic results similar to those in the 2005 Trustees Report. Add PSG model benchmark runs that use intermediate-cost assumptions from the 2006 Trustees Report. Add low benefits-plus-earnings avoidance rate statistic to the GEMINI .sum output file.

2006-Apr
No enhancements.

2006-Mar
Add options for SSASIM to produce .sti and .sto output files in OLC mode runs. Improve logic of DI-to-OAI conversion for cohorts with fractional normal retirement ages, producing a smoother flow of beneficiaries from DI to OAI during years when the normal retirement age is increasing by a fraction of a year. Fix a bug in the calculation of PIA for individuals who experience a disability or death event after age 62 and before the retirement event. Add to SSASIM "scaled earnings" calculated by OCACT using 2005 Trustees Report assumptions.

2006-Feb
No enhancements.

2006-Jan
Upgrade to a newer version of the Open Watcom C++ compiler to build the PSG models, resulting in roughly a ten percent reduction in run execution time. Change the run specification file PENSIM preamble generated by the RSF Toolkit so that there is no emigration of foreign-born individuals, which is a highly unrealistic assumption, but one that aligns the PSG models with assumptions made in the Trustees Report and in the CBO CBOLT model.

2005-Dec
Revise PENSIM so that it directly writes binary coh files in the OLC and RCS modes of operation. Add OLC mode logic to PENSIM that forces immediate death of cohort sample individuals and their spouses in the year following the last simulation year in SSASIM. These two changes in the PSG models have no effect on output results, but reduce the execution time for an OLC run by about fifty percent. Fix a bug in the calculation of enhanced PIA (as in the CSSS reform proposals) and the minimum PIA (as in the Graham reform proposal) that was caused by assuming quarters of coverage are counted back to age 21 instead of age 22 (as in those reform proposals). Fix a bug in the calculation of minimum PIA for DI beneficiaries being converted to retired-worker beneficiaries under the Graham minimum PIA reform provision. Add GEMINI .scn output file containing aggregate statistics for the cohort sample in each scenario.

2005-Nov
Add a policy parameter that allows the maximum social security account contribution rate to vary over time.

2005-Oct
Add ability to specify (deterministic or stochastic) macrodemographic and macroeconomic assumption parameters using the run specification language in the RSF Toolkit. Add statistics to SSASIM .pod output file that report the age composition of the population. Add aggregate taxable earnings to the SSASIM .ben output file.

2005-Sep
Continue developing the RSF Toolkit, which will eventually become the user interface to the PSG models. Add policy parameter that enable specification of reforms that involve the scaling down of PIA-formula fractions for the DI eligibility event in a way that differs by eligibility age, by calendar year, and by formula fraction (i.e., in a "progressive" manner).

2005-Aug
No enhancements.

2005-Jul
Provide the first, incomplete version of the RSF Toolkit, which will serve as the new interface to the PSG models, providing the ability to specify a new model run using a simple run specification language without having to manipulate the model input databases by hand. Add several policy parameters to allow specification of reforms that establish non-linear excess payroll tax rate schedules.

2005-Jun
Add policy parameters that enable specification of reforms in which the bottom two and the top two OASDI PIA fractions decline at different rates (i.e., the "progressive indexing" of benefits). Add a policy parameter that allows specification of reforms in which disabled-worker beneficiaries are not converted to retired-worker beneficiaries at their normal retirement age. Add a policy parameter that allows specification of reforms in which disabled workers are not allowed access to DI benefits, and must take reduced early retirement benefits, if their age is greater than or equal to the early retirement age. Improve the resclean utility so that it automatically detects output files to delete in all three PSG model working directories.

2005-May
Introduce automatic installation and version upgrade capabilities. Provide initial version of the dbrun-create utility that automates some aspects of creating a new run in the PSG model input databases; this requires some revisions to the structure of the several SSASIM tables. Correct a bug that read the fraction of newborns who are girls as an integer rather than a real value.

2005-Apr
Add benchmark runs to the PSG model input databases that incorporate intermediate-cost assumptions from the 2005 Trustees Report. Streamline the specification of spouses and children of exemplary cohort individuals (ECI) in the SSASIM input database. Add a statistic to the SSASIM .pod output file that reports the population aged 65 or more in each simulation year. Add to PENSIM the ability to reset all random number streams at the start of each scenario, which permits simulating the exact same sample of cohort individuals in each scenario (when the reset parameter is true) or a different sample of cohort individuals in each scenario (when the reset parameter is false); the later is more reliable because there is no chance that the single scenario sample is statistically unrepresentative of the cohort population.

2005-Mar
Revise PSG model logic so that it is possible to specify an OLC mode run that has as many as 900 years in the actuarial test period (rather than the 75 years used in the Trustees Report). Simplify the specification of exemplary cohort individuals (ECI) in the SSASIM input database using OCACT "scaled earnings" as the default earnings history. Add a new OASI and DI payroll tax rate parameter that allows taxation of earnings above the maximum taxable earnings (MTE) without using the above MTE earnings in OASDI benefit calculations. Add new social security account policy parameter that allows a positive contribution rate on earnings above the MTE. Provide a command-line dbrun-delete utility that deletes from model input databases all rows used by the specified run that are not used by any other runs. Provide a command-line hist2d utility that produces two-dimensional histogram graphs from GEMINI output files.

2005-Feb
Streamline the specification of social security accounts in several ways. Add new DI policy parameter that allows specification of Graham reform proposal for DI PIA calculation when PIA fractions are declining. Revise the assumption about the timing within a calendar year of the payment of OASDI taxes and the receipt of OASDI benefits so that cashflows are assumed to occur at the start of the year, bringing the micro ECI and RCS modes of operation into line with the assumptions used in the macro CBA and OLC modes of operation. Add a GEMINI annuity provider revenue and cost output file that reports the solvency of the social security account annuity provider, which provides statistics needed to determine the pricing of annuities that will ensure the solvency of the provider.

2005-Jan
Add a fourth automatic adjustment method for the OASDI PIA formula fraction that sets this year's fraction equal to last year's fraction, which allows reforms that stop benefit "indexing" in some future year. Simplify the modeling of social security account clawbacks. Improve the logic used to estimate trust-fund income produced by the income taxation of social security benefits. Revise PENSIM job-start logic so that individuals never start a new job late on New Year's Eve. Add two statistics to the GEMINI .sum output file that report the lifetime present value of OASI and DI benefits received from the DB tier of social security.

2004-Dec
Add DI-to-OAI conversion logic option required to characterize the Graham proposal. Add two new statistics to the GEMINI .sum output file that record the age at which the first OASDI benefit is received and the dollar amount of that first benefit.

2004-Nov
Add ability to specify various automatic adjustments (or "indexing") methods for the fractions used in the OASDI PIA formula, which allows easier specification of the CSSS reform proposals and correct simulation of CSSS plan 2 under stochastic assumptions that imply variation in real wage growth across macroeconomic scenarios. Add ability of not applying the minimum PIA policy to PIA calculations at the disability event, which allows that specification of the minimum PIA policy contained in the Graham reform proposal.

2004-Oct
No enhancements.

2004-Sep
Add ability to increase the number of dropout years in the OASDI AIME formula, which adds flexibility to the longstanding ability to reduce the number of AIME dropout years. Add ability to specify a nonlinear minimum PIA formula as in the most recent Kolbe-Stenholm bill (see OCACT memo dated 2/11/04). Add ability to specify a maximum retired-worker spousal benefit as in the most recent Kolbe-Stenholm bill. Add to the PSG models distribution two new output analysis utilities, mean and pctiles, that quickly tabulate at the Windows command prompt the mean and percentile distributions of any statistic in GEMINI .sum and .bAA output files.

2004-Aug
No enhancements.

2004-Jul
No enhancements.

2004-Jun
Add new PSG model benchmark runs that use 2004 Trustees Report intermediate-cost assumptions.

2004-May
Add to the binary env file generated by SSASIM for PENSIM input OASDI statistics required for offset-integration benefit calculation logic for some defined-benefit pension plans. Add to the GEMINI .sum output file a second OASDI internal rate of return statistic so that the old statistic is computed using individual tax and benefit cashflows and the new statistic is computed using family-size-adjusted couple tax and benefit cashflows. Add age of disability onset and age of disability recovery to GEMINI .bAA output file.

2004-Apr
No enhancements.

2004-Mar
Change the assumption used in calculating summarized cost rates, summarized income rates, and the actuarial balance, concerning the timing of cashflows within each calendar year. Prior versions of SSASIM assumed that cashflows involved in the calculation of these present value statistics occur at the end of the calendar year. But Trustees Report Table IV.B6, which appeared for the first time in the 2003 report (see page 61), implies that the Office of the Chief Actuary assumes that the cashflows occur at the beginning of each calendar year in these present value calculations. The same within-year timing assumption is made beginning with this version of SSASIM. This change in present-value-calculation logic causes small changes in the summarized rates.

2004-Feb
Add SSASIM .ben output file that contains annual OASI and DI beneficiary head counts as well as annual values of the SSA average wage index (AWI), the CPI index, and OASDI maximum taxable earnings (MTE). Update PENSIM input parameters so that OLC mode runs use 2003 Trustees Report intermediate-cost assumptions same as CBA mode runs. Add ability to specify whether or not GEMINI computes an OASDI internal rate of return statistic for each individual, and whether or not the cashflows used in the calculation are individual or couple taxes and benefits. Add to GEMINI an annual actuarial adjustment factor (AAAF) to enable OLC mode runs using 2003 Trustees Report intermediate-cost assumptions to simulate aggregate future benefits that are as high as reported in the 2003 Trustees Report. The AAAF feature allows users to either use standard microsimulation methods and get lower benefits (as in the CBO CBOLT model) or to use the AAAF to emulate the higher benefit shown in the 2003 Trustees Report.

2004-Jan
Add features to support new OLC mode of operation, including a SSASIM population detail .pod output file, and immigration and emigration behavior in PENSIM. Add new OAI policy parameter that controls size of auxiliary child benefits so they can differ from auxiliary spouse benefits. Add present value of taxable earnings statistics to SSASIM .ssa output file. Add statistics to GEMINI .sum output file that adjust couple benefits, taxes, and earnings for family size, using two user-defined parameter values and a family size equivalence formula from a 1995 National Academy of Sciences report. Add this family size equivalent statistic to the GEMINI .adq output file.

This page was last revised on February 20, 2010.

PolicySimulationGroup

Pension Projection Models

Enhancements Introduced in Earlier Versions of the PSG Models (since 2004)

Policy
Simulation
Group