We built GiveCalc because most donation calculators just multiply by your tax bracket. That misses a lot: standard vs. itemized thresholds, state taxes, future-dated policy, new HR1 provisions. PolicyEngine's tax models handle the full complexity. GiveCalc makes them accessible.

Important read on fiscal transparency. While CBO is taking commendable steps by expanding its GitHub presence, Rauh & Jaros are right: full replicability should be the standard for them and JCT. Open source builds trust and accuracy. www.wsj.com/opinion/the-...

Great to see Rep Tlaib's team use PolicyEngine to design her new policy reform.

I had a blast making this with Claude Code - both the animation and the spooky soundtrack, which it composed in Python. github.com/policyengine...

Our AI journey continues - excited to share our Claude Code plugin soon!

Something about being in California brings out the ballot measure analyst in me!

Heading to LA this week for Benefit Navigator's event. Their platform helps families and case managers navigate public benefits and tax credits - powered by the @us.policyengine.org API for tax and benefit calculations. Excited to see tech and policy come together to expand access.

Tomorrow evening I'll be celebrating the 13th anniversary of the @opengovhub.bsky.social, @us.policyengine.org's new home in DC. I'll also give a short talk on our work to promote open governance and transparency, the mission of the space and our neighbor organizations. Tickets still available!

Disappointed that the plant-based Shouk, my favorite fast-casual place in DC, has closed. Anti-Israel groups targeted it because an Israeli immigrant owned it, and are now cheering their victory.

Agentic AI coding tools continue to inspire us to turn everything into software. Join us at our new home in downtown DC, the @opengovhub.bsky.social, for a celebratory happy hour on Oct 22: luma.com/lnrzph2h

Our new ACA calculator shows how extending the enhanced premium tax credits would affect households. An extreme case: A 64-year-old in Fairbanks, AK would gain $655 in 2026 if they earn $61k, but gain $26,861 if they earn $62k. Try it here: policyengine.org/us/aca-calc

Come by tonight if you're in London!

The Prenatal-to-3 Policy Impact Center just launched their new Policy Impact Calculator, which uses @us.policyengine.org for federal and state tax modeling. Great example of research infrastructure enabling better policy decisions for young children and families. pn3policy.org/policy-impac...

Enjoyed my conversation with the SVIC Podcast about how @policyengine.org uses Claude Code to democratize economic policy analysis. Watch here: youtu.be/4apWdJR9-iY?...

Can't wait for our first live event in London! If you're in the area and interested in policy simulation, I think you'll discover major new possibilities our new app and research will offer. See you there: eventbrite.co.uk/e/policyengi...

We constructed fully synthetic firm microdata to conduct this analysis. I was struck how calibrating to a large range of coarse aggregates could result in microdata that reveals sharp responses to cliff effects. You could run a bunching study on this synthetic data! (And we will.)

This partnership exemplifies why we built PolicyEngine: policy analysis tools should be open, accessible, and sustainable. Honored that NBER trusts us to ensure TAXSIM—the foundation of tax research for decades—continues serving researchers while evolving for modern needs.

Today, @telegraphnews.bsky.social suggested that raising the UK VAT registration threshold would increase revenues in the long run. This misread (poorly documented) government projections, which reflected inflation adjustments in the baseline. My latest: substack.com/home/post/p-...

I've been using Claude Code a LOT lately ($5,800+ in tokens last month on my $200 Claude Max plan), and now experimenting with custom slash commands and subagents. Here's an example: using parallel subagents to independently write integration tests and encode policies for @us.policyengine.org.

🎉 PolicyEngine has been awarded a $300,000 Phase I POSE grant from NSF (Award No. 2518372) to expand our open-source platform, build sustainable governance, and grow our contributor community! https://policyengine.org/us/research/nsf-pose-phase-1-grant

Bumping the cap to $62k/124k would benefit 22% of US residents in the top income decile and 1.2% of those in the bottom 90%.

The SALT cap would raise taxes on 22% of Americans in the top income decile, and 3% of Americans in the bottom nine deciles.

Chatted with @kimberlyadams.bsky.social of @marketplace.org about the Ways & Means draft to extend 2017 individual tax cuts. The full bill is now out—SALT tweak, tip & OT deductions, and more. Crunching the numbers in @us.policyengine.org—stay tuned for results. 🎧 www.marketplace.org/story/2025/0...

JCT projects the Ways & Means draft would add $4.9 trillion to the debt by 2035. Tuesday's number could be lower (SALT cap) or higher (exemptions of Social Security, tips, overtime, etc.) on the individual side. And higher if provisions ending in 2028 are extended. www.jct.gov/publications...

The new W&M draft increases the maximum CTC from $2,000 to $2,500 from 2025 to 2028. From 2029 onwards, it then sets it to $2,000, inflation-indexed with a 2024 base year. Applying CBO inflation projections yields: 2029-30: $2,200 2031-33: $2,300 2034-35: $2,400

New Ways & Means draft extends TCJA's AMT provisions while letting the SALT cap expire. Since AMT limits SALT benefits, filers would gain more from SALT than they did pre-TCJA. For example, a joint filer with $250k income faces these effective SALT caps in 2026: Current law: $38,876 W&M: $72,747

New poll from @umich.edu Institute for Healthcare Policy & Innovation: 62% of adults age 50+ think Medicare would pay for their care if they need to permanently move into a nursing home. People age 65+ & those with disabilities disproportionately believe this. Medicare doesn't cover long term care.

Cutting the trade deficit is a controversial goal. But if you did want to, what levers would you pull? I asked o3 to identify some, along with estimates and CIs. It estimated that tool usage would shrink its CIs by 20-40%. Motivating for our work arming AI with models via MCP.

Yesterday at the Future of Think Tanks Hackathon, @pavelmakarchuk.bsky.social, Daphne Hansell and I built a prototype tool to generate legislation from @policyengine.org simulations using LLMs. We hope to integrate this into the platform soon. Try it here: policyengine-legislation.streamlit.app

My latest for Earth Day 👇

We all know the difficulty of counting the r's in "strawberry", but what about other fruits, or even other letters? This combinatorics problem grows exponentially, but with the help of Claude Code, I've built a tool to solve it, at least for common fruits. Here it is in action:

Just back from EA Global SF with the @policyengine.org team! Incredible conversations with folks tackling the world's most pressing problems. With AI transforming society at unprecedented speed, our work on transparent policy simulation feels more urgent than ever.

DC residents have income higher than any state and 53% higher than the national average.

A single parent of one with $14,200 earnings can claim a $4,328 EITC in 2025, per @policyengineus.bsky.social. Deepseek and Claude estimated this most accurately (though Deepseek thought about it for over three minutes!); Gemini estimated least accurately.

Would @kalshiofficial.bsky.social say that Biden "reduced the national debt" because it fell 0.35% from Q2 to Q3 2021?

The Census Bureau has taken down American Community Survey microdata. Thankfully we had a local copy, and now store it on @policyengine.bsky.social servers.

The Census Bureau temporarily removed Current Population Survey microdata today as part of a broader federal website shutdown targeting demographic and statistical information. This disruption broke @policyengineus.bsky.social's build process and affects critical analysis across sectors.

@hshierholz.bsky.social yesterday at the NASI conference you mentioned that life expectancy has fallen among the poor. I see studies (e.g. this from EPI) showing that it's risen faster among the rich but not that it's fallen among the poor, could you share it? www.epi.org/publication/...

My tests of Deepseek so far indicate consistently weaker performance than o1-pro & also regular o1 on basic applied theory tasks in econ. Often o1-mini also outperforms it. More interestingly, Gemini's latest "thinking" model outperforms Deepseek on my tasks more often than not.

This, to me, is a fascinating dimension of DeepSeek. It censors itself (on the hosted version, as everyone knows). But it's also a train of thought model. So you can actually see its "thought process" on some topic, before it realizes it can't talk about the topic

Fresh tax market manifold.markets/MaxGhenis/wh...

A fun new tool from @maxghenis.bsky.social : a calculator for charitable contributions, including both state and federal effects and interactions with other deductions. Lots of other good bells and whistles. @nicduquette.bsky.social should be into this. policyengine.org/us/research/...

As 2024 draws to a close, I'm reflecting on my coding journey. Leading @policyengine.bsky.social meant less time programming, but I still maintained 3,721 GitHub contributions this year (down from ~4,500 in recent years), spanning collaborations, third-party contributions, and personal projects.

After months of internal testing and refinement, excited to finally launch this publicly! This is what modern policy analysis should look like: dynamic, transparent, and cross-national.

In September, I previewed PolicyEngine's AI explanations at Georgetown's BenCon conference. Today, we're launching this feature to help everyone understand their taxes and benefits. 🚀

New study of @bouldercolorado.bsky.social guaranteed income pilot documents changes in participant circumstances after vs before receiving $500/month, especially in psychological wellbeing and food security. But with no control group or other causal ID strategy, impact claims aren't justified.

I asked o1-pro to think through a political economy model with: * Heterogeneous social welfare among candidates, * Endogenous turnout driven by expected difference in outcomes, and * Noisy perceptions that can be improved by education. Here's a single response (following a larger chat).

Free, open-source policy analysis tools are essential for evidence-based policymaking. Grateful for NEO Philanthropy's support in expanding access to sophisticated microsimulation modeling.