As 2021 winds down, I wanted to take a few minutes to reflect on the Policy Simulation Library’s efforts over the past year. With an amazing community of contributors, supporters, and users, PSL has been able to make a real impact in 2021.

The library saw two new projects achieve “cataloged” status: Tax Foundation’s Capital Cost Recovery model and the Federal Reserve Bank of New York’s DSGE.jl model. Both models satisfy all the the PSL criteria for transparency and reproducibility. Both are also written entirely in open source software: the Capital Cost Recovery model is in R and the DSGE model in Julia.

An exciting new project to join the Library this year is PolicyEngine. PolicyEngine is building open source tax and benefit mircosimulation models and very user-friendly interfaces to these models. The goal of this project is to take policy analysis to the masses through intuitive web and mobile interfaces for policy models. The UK version of the PolicyEngine app has already seen use from politicians interested in reforming the tax and benefit system in the UK.

Another excellent new addition to the library is the Federal-State Tax Project. This project provides data imputation tools to allow for state tax data that are representative of each state as well as federal totals. These datasets can then be used in microsimulation models, such as Tax-Calculatorto study the impact of federal tax laws across the states. Matt Jensen and Don Boyd have published several pieces with these tools, including in State Tax Notes

PSL community members continued to interact several times each week in our public calls. The PSL Shop was launched in 2021 so that anyone can get themselves some PSL swag (with some of each purchase going back to the PSL Foundation to support the Library). In addition, PSL hosted 20 Demo Day presentations from 11 different presenters! These short talks covered everything from new projects to interesting applications of some of the first projects to join the Library, as well as general open source tools.

As in past years, PSL cataloged and incubating models were found to be of great use in current policy debates. Whether it was the ARPA, Biden administration proposals to expand the CTC, or California’s Basic Income Bill, the accessibility and ability to reproduce results from these open source projects has made them a boon to policy analysts.

We are looking forward to a great 2022! We expect the Library to continue to grow, foresee many interesting and helpful Demo Days, and are planning a DC PSL Workshop for March 2022. We hope to see you around these or other events!

Best wishes from PSL for a happy and healthy New Year!

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