PIP point system (partly modelled) - PolicyEngine UK documentation

Status, October 2026

A first step merged on 21 October 2026 as #1661: total points inputs (pip_dl_points, pip_m_points) and the 8- and 12-point thresholds under gov.dwp.pip.{daily_living,mobility}.points_thresholds. The category is derived from points only when no category is given as an input for the year. A category given for a year is stored for everyone in the simulation, with NONE for anyone not given one. Otherwise the person’s latest assessed points (not -1) for that year or an earlier one set the category, except that a category given for an earlier year carries forward unless those points are for a later year than it; with neither, the category is NONE (policyengine_uk/utils/pip.py). That is a simpler form of Phase 1 below: no per-activity scores and no use_point_system switch, since a category input already takes precedence over the formula.

No data path supplies points yet. The datasets store categories, not points, so points play no part in microsimulation. The companion PR, policyengine-uk-data #408 (points imputed from the observed categories), was closed in June 2026 in the uk-data archive clean-up, with PIP points derivation to move into Microcosm UK’s source stages (microcosm #145) once the input variables existed here. Microcosm #145 closed on 16 October 2026 with that item dropped, because the variables did not exist yet.

What PIP scoring actually is¶

The Personal Independence Payment is awarded on a points-based assessment defined in Schedule 1 to SI 2013/377 (the Social Security (Personal Independence Payment) Regulations 2013):

Part 2: Daily living activities: ten activities (preparing food, taking nutrition, managing therapy, washing and bathing, managing toilet needs, dressing and undressing, communicating verbally, reading and understanding signs, symbols and words, engaging with other people face-to-face, making budgeting decisions). Each activity has a set of descriptors with point values from 0 up to 12; the top value varies by activity.
Part 3: Mobility activities: two activities (planning and following a journey, moving around), each with descriptors worth up to 12 points.

The award rule:

Total points (per component)	Award
0–7	None
8–11	Standard rate
12+	Enhanced rate

Daily living and mobility are scored independently, so a claimant can be on standard daily-living and enhanced mobility, or any other combination.

Why the current categorical model is reasonable for microsim¶

For population-aggregate simulation, the categorical bands are sufficient because:

the FRS doesn’t capture activity-level point scores at all,
DWP’s regular PIP statistics report the caseload by award level (standard / enhanced) rather than activity scores; per-activity figures appear only in one-off publications such as the evidence-pack tables cited under Phase 3,
the data (both Microcosm UK, the certified default since October 2026, and the Enhanced FRS from policyengine-uk-data, which it replaced) sets pip_dl_category and pip_m_category by comparing the weekly PIP daily-living and mobility amounts respondents report in the FRS with the standard and enhanced rates.

So for headline distributional and fiscal analysis the categorical inputs are correct.

Where the point system would matter¶

Three reform scenarios that the categorical model can’t answer:

Activity-level descriptor reform: for example, the April 2024 green paper consulted on changing the descriptors, and the March 2025 Pathways to Work green paper proposed requiring at least four points in one daily-living activity for the daily-living component. The government withdrew the four-point change in July 2025, pending a review of the PIP assessment. A categorical input can’t capture this; the categorical band wouldn’t shift unless an analyst manually re-bands a synthetic distribution.
Threshold reform: changing the band thresholds (for example raising the standard-rate floor from 8 to 10 points). The thresholds are now parameters, so this works for households entered with points, but not in microsimulation, where the data supply bands rather than points.
Targeted analysis by descriptor: distributional questions like “how does the enhanced cohort split between mobility activities” need the underlying activity scores.

Proposed scope¶

Phase 1: points-to-category mapping¶

Threshold parameters: done in #1661 as gov.dwp.pip.{daily_living,mobility}.points_thresholds.{standard,enhanced} (8 and 12).
Add per-activity score inputs as pip_dl_activity_1_score ... pip_dl_activity_10_score, pip_m_activity_1_score, pip_m_activity_2_score. Type: integer (Person, YEAR), default 0.
Add derived variables pip_dl_total_score and pip_m_total_score summing the activity scores.
Add pip_dl_category_from_points and pip_m_category_from_points that look up the band from the total score against the threshold parameters.
Keep pip_dl_category / pip_m_category as the input the rest of the model reads, with a new switch parameter gov.dwp.pip.use_point_system (default false) that, when true, overrides the categorical input with the points-derived band.

This is a strict superset of the current model: the categorical input remains authoritative by default, and analysts opting into the points machinery (for reform analysis) get the activity-level surface.

Phase 2: descriptor-level parameters¶

Per-activity descriptor tables under gov/dwp/pip/descriptors/, encoding the point value of each descriptor in SI 2013/377. The representation can be flat (one YAML per activity with a list of (descriptor_id, points) entries).
A pip_dl_activity_1_descriptor (etc.) enum input that selects which descriptor applies; the activity score is then a parameter lookup.
Reform-side: descriptor point values are then parameters that can be perturbed for “what if descriptor X scored 4 instead of 6” analyses.

Phase 3: data-side imputation¶

The FRS provides PIP payment amounts but not descriptor selections. The data (Microcosm UK, as the replacement dataset) would need to impute descriptor selections per claimant that are consistent with the observed band. The plausible approach is to draw descriptor combinations whose total falls in the observed band, weighted by the point-score distributions for each daily-living activity that DWP published in the Pathways to Work evidence pack (chapter 2, Tables 2.27 and 2.28: working-age, normal-rules claimants awarded the daily living component in England, Wales and abroad, January 2025 caseload; the pack has no per-activity mobility table).
This phase is the heaviest and is only required to make Phase 2 reforms work on the calibrated microsim. For the household calculator, users can input activity scores directly.

Open questions¶

Should the score inputs default to None (sentinel) or 0? Sentinel is cleaner when the points machinery is opt-in via the use_point_system flag. (#1661’s total points inputs use -1 for “not assessed”.)
DWP’s PIP review process distinguishes “ongoing” vs “fixed-term” awards. Should the model expose the award duration, or treat all current awards as ongoing? (Current model assumes ongoing.)
The outcome of the PIP assessment review may change descriptors or the scoring rule; the descriptor-parameter design in Phase 2 should make such changes a parameter edit.

References¶

The Social Security (Personal Independence Payment) Regulations 2013 (SI 2013/377): Schedule 1, Parts 2 and 3 define the point system.
DWP, Personal Independence Payment: Assessment guide.
DWP, PIP statistics: caseload by component and band.
DWP, Modernising support for independent living: the health and disability green paper (April 2024): proposals on the descriptors.
DWP, Pathways to Work: Reforming Benefits and Support to Get Britain Working (March 2025): the four-point proposal.
Issue: #1069.
Existing model: pip_dl_category, pip_m_category, pip_dl_points, pip_m_points, pip_dl, pip_m, and the thresholds under gov.dwp.pip.{daily_living,mobility}.points_thresholds.