Max Ghenis

Duplicate of #560 and/or #460?

Attaching the contents as the zip file was blocked by default for me [postcodesector_2_brma.csv](https://github.com/PolicyEngine/policyengine-uk/files/13451348/postcodesector_2_brma.csv) [ladistrict_2_brma.csv](https://github.com/PolicyEngine/policyengine-uk/files/13451349/ladistrict_2_brma.csv)

FWIW I only saw one income level where the spline was obviously nonmonotonic, so might not be such a high priority: https://policyengine-uk-documentation.nw.r.appspot.com/Capital_Gains_Tax

The [PCHIP Interpolator](https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.PchipInterpolator.html) seems ideally suited to this. It both preserves monotonicity and supports extrapolation. Here's an example for the 99th income centile, which the spline currently produces a nonmonotonic...

Just bringing this back up. We show in the [parameter page](https://policyengine.org/uk/policy?focus=gov.dwp.pip.daily_living.enhanced&reform=43670&region=uk&timePeriod=2024&baseline=1) that it doesn't affect simulations, yet it does. It doesn't seem to be just random noise for any null...

Looks like the imputation and reweighting data aren't in the repo now that the data portion moved to openfisca-uk, is that right? Should we publish them as releases instead of...

this still relevant?

Moving to icebox as this functionality isn't really used - it's all in policyengine Should they still be in this package?

To clarify, is issue to initialize weights of each UC/legacy replicate record as `original_weight * where(UC, UC_rollout, 1-UC_rollout`?

Are take-up rates represented as policy parameters in UKMOD as they are in openfisca-uk? If so we could set them to 1. Sharing test cases could also be a good...