PolicyEngine / policyengine-uk

The UK's only open-source static tax-benefit microsimulation model.
https://policyengine.github.io/policyengine-uk/
GNU Affero General Public License v3.0
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Compare to Landman Economics simulation #43

Open MaxGhenis opened 3 years ago

MaxGhenis commented 3 years ago

It'd be interesting to see how this compares to simulations from Landman Economics.

For example, the RSA report, "A Basic Income for Scotland," uses the Landman model and comes up with these figures: image

image

I think this MTR chart is for a lone parent with two children, as referred to below the chart. image

(The report doesn't show equivalent reforms together, but Horizon 2 preserves existing tax rates.)

Not a high priority given the significance of the task, but could be a good validation point.

nikhilwoodruff commented 3 years ago

Thanks, this graph is really interesting. One thing I'm not sure about is where exactly the Child Benefit High-Income Tax Charge appears in this graph - should be a raised level between £50k and £60k I think: https://www.gov.uk/child-benefit (1% of received child benefit is added to income tax for every £100 over £50k/year).

After I push a small bug fix on said High-Income Tax Charge, we get this: image

nikhilwoodruff commented 3 years ago

With the main components broken down: image

nikhilwoodruff commented 3 years ago

(The High-Income Tax Charge is effectively a means test for Child Benefit, but it's a component of Income Tax so doesn't stack). In summary, we match most of it, but there's:

MaxGhenis commented 3 years ago

Great MTR decomposition chart. Might the rules have changed in the past couple years?

nikhilwoodruff commented 3 years ago

Sure, Universal Credit rates fluctuate, but the HITC as far as I'm aware has always been at £50k since its introduction in 2013.