PolicyEngine UK

We provide free, open source software to compute the impact of public policy. See our global account @ThePolicyEngine and US account @PolicyEngineUS.

[PolicyEngine UK @PolicyEngineUK]

Explore the analysis: https://t.co/8GMvM7kVEc

[PolicyEngine UK @PolicyEngineUK]

Replacing the State Pension triple lock from 2030, across 50,000 paths of prices and earnings:

• Saving in 2039-40: £11.1bn gross, £7.9bn net of tax and benefits
• Full new State Pension £931/yr lower on average
• 27% of households with less income

[PolicyEngine UK @PolicyEngineUK]

Read more: https://t.co/Kikn2YbWAq

[PolicyEngine UK @PolicyEngineUK]

We estimate the £2 bus fare cap in England outside London costs £409m in total. The £3-to-£2 cut alone costs £273m. Modelled households save £18.20 a year on average.

[PolicyEngine UK @PolicyEngineUK]

Try it: https://t.co/YN2olTwKYg

[PolicyEngine UK @PolicyEngineUK]

How does living together change a couple's taxes and benefits? Our calculator compares a couple living as one household with the same two people living apart, for 2026-27 to 2029-30 across the UK nations.

[Max Ghenis @MaxGhenis]

I've traded 22 of @PolicyEngineUK's play-money Budget markets this week. On the reporting, I now put a bank tax rise at 75%, a main CGT rate rise at 20% and a lower mansion tax threshold at 15%.

We've also opened seven new ones. Trade against me: https://t.co/sIaSTRJ80s

[PolicyEngine UK @PolicyEngineUK]

At 4:30pm GMT on Budget day, Wednesday 28 October, we'll present our first estimates of what the Autumn Budget means for public finances, household incomes and poverty, and take your questions.

Register free: https://t.co/D6QkQ4wZFD

[PolicyEngine UK @PolicyEngineUK]

Five years ago today PolicyEngine launched in the UK to democratize evidence-based policy, so that anyone can change a tax or benefit rule and see what it means for their household and the country.

Thank you to everyone who has built it with us, and to everyone who uses it.

[PolicyEngine @ThePolicyEngine]

We're at the International Microsimulation Association World Congress in Brussels, 1–3 July. Three talks:

• Maria Juaristi — local microdata calibration with L0 regularisation

• @vahiidahmadi — firm microsimulation + VAT

• @MaxGhenis — hands-on PolicyEngine tutorial

[PolicyEngine UK @PolicyEngineUK]

New peer-reviewed, open-access paper: PolicyEngine microsimulation helped 39 UK citizens deliberate real fiscal-policy trade-offs during the cost-of-living crisis — a method later adopted by the UK Climate Change Committee. https://t.co/W7FiiWGohm

[Rick Evans @RickEcon]

@MaxGhenis and @ThePolicyEngine team have integrated frontier agentic AI into the most expansive open source microsimulation model of US fiscal policy. AI allows easier use and access as well as automates much of the model creation and maintenance.
https://t.co/QCnXtVEMsz

[PolicyEngine UK @PolicyEngineUK]

We just launched a plugin that brings PolicyEngine to @claudeai.

Describe any tax or benefit reform in plain English. Claude runs a full microsimulation using our open-source model — 700+ variables, 1,200+ parameters, NI to UC.

No code required.

https://t.co/B9uvCqUXWB

[Peston @itvpeston]

Can the government solve the student loan crisis in England and Wales? 💷

And does the system work better in Scotland? 🏴󠁧󠁢󠁳󠁣󠁴󠁿

Watch our analysis featuring new modelling from @PolicyEngineUK and let us know what you think should be done👇

#Peston

[PolicyEngine UK @PolicyEngineUK]

Happy Valentine's Day! We just launched PolicyEngine's marriage calculator.

Find out if saying "I do" means a bonus or penalty for your household — from the marriage allowance to Universal Credit.

Try it: https://t.co/LfERdG2gps

[PolicyEngine @ThePolicyEngine]

Join our webinar today at 1:30PM ET to learn more!

https://t.co/bwq62CfUq4

[PolicyEngine @ThePolicyEngine]

https://t.co/j3ufyGAeFu

[PolicyEngine UK @PolicyEngineUK]

Our new dashboard analyses the Scottish Budget 2026-27:

📊 £64m cost in 2026-27 → £196m revenue by 2030-31
📈 Threshold uplifts, SCP expansion, rate freezes
🏠 Household calculator to see your impact

Explore: https://t.co/Wq1js4ZKy3

[Nikhil Woodruff @nikhil_woodruff]

1/3 Excited to share this! For the past 6 months I've been working with the powerhouse No 10 Data Science team @10DowningStreet to push the speed and accuracy boundaries of tax-benefit policy analysis with @ThePolicyEngine 's open source technology.

[PolicyEngine UK @PolicyEngineUK]

Read Nikhil's article: https://t.co/4tZPFy9ZGP

And more on our blog: https://t.co/WZffGx351L

[PolicyEngine UK @PolicyEngineUK]

PolicyEngine is now powering rapid policy analysis at 10 Downing Street.

Our co-founder and CTO @nikhil_woodruff spent 6 months with the 10DS data science team as an Innovation Fellow, adapting our open-source microsimulation model for government use.