Pension Projection Models
PENSIM has been under continuous development since 1997, when DOL/EBSA awarded the initial development contract. A no-pension version of PENSIM provided life histories for GEMINI social security simulation between 2001 and 2008. Beginning in early 2007, the publicly distributed version of PENSIM has been able to simulate employer-sponsored pensions. Since 2008, PENSIM has provided GEMINI with pension information necessary to apply the social security WEP/GPO benefit reduction rules.
SSASIM has been under continuous development since 1994, when it started as part of the work of the Social Security Advisory Council. Development was sponsored by EBRI for several years during the late 1990s. Since 2000, the development of SSASIM has been sponsored by the Policy Simulation Group and by users of the PSG models, with major enhancements supported by SSA/ORDP.
GEMINI was initially developed in 2001 by the Policy Simulation Group to create a social security microsimulation capability by combining the life history simulation capabilities of PENSIM and the social security tax and benefit simulation capabilities of SSASIM. Then beginning in 2004 with support from SSA/ORDP, SSASIM was enhanced to use this GEMINI microsimulation capability to produce solvency estimates for the social security trust funds.
There is a detailed description of enhancements introduced in current version of the PSG models.
There is a summary of enhancements introduced in earlier versions dating back to January 2004.