docs: compare-screen redesign spec, expert review, and data-foundation plan

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0146VHeLAWjDVE2B5uU67jCB

docs/superpowers/specs/2026-07-11-compare-screen-expert-review.md

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+# Compare Screen Redesign — Expert Data Review
+
+**Date:** 2026-07-11
+**Reviewer:** subagent briefed as an English education-standards / DfE-Ofsted data expert
+**Subject:** desktop + mobile compare mockups and the redesign spec
+(`2026-07-11-compare-screen-redesign-design.md`)
+**Status:** first-pass must-fixes applied 2026-07-12; second-pass
+findings (below) applied 2026-07-12 — mockups + spec §4/§8 updated
+
+## Must-fix
+
+1. **COVID gap is wrong and drops a real results year.** KS2 tests were
+   cancelled 2019/20 and 2020/21 only; they resumed in 2021/22 with
+   published school-level results (England RWM ≈ 59%). The mockup charts
+   omit 2021/22 entirely and the tooltip claims no tests were held
+   2019/20–2021/22. Fix: add 2021/22 to axis and all series; shrink the
+   gap band; optionally annotate 2021/22 with DfE's post-pandemic
+   comparability caution.
+2. **Report-card at-a-glance summary miscounts areas.** Detail list has
+   4 Strong / 2 Expected / 1 Attention needed + Safeguarding met, but
+   the summary says "3 areas Expected standard" — it counts safeguarding
+   as a graded area. Safeguarding is a separate binary judgement and
+   must be excluded from rating counts.
+3. **"Where the offers went" derivation is unsound.** Places − 1st-pref
+   offers ≠ "second or third choices": the residual can include 4th–6th
+   preference offers (pan-London scheme) and LA-allocated children who
+   didn't choose the school; and offers don't necessarily equal PAN.
+   Use the real 2nd/3rd-preference fields being promoted from
+   `raw.ees_admissions`; until then drop the row.
+4. **Ofsted timeline in the copy is wrong.** Overall grades were
+   abolished September 2024, not November 2025; Sept 2024–Nov 2025
+   inspections kept the four key judgements without an overall grade
+   (ungraded inspections carried grades forward). Neither mockup shows
+   the interim regime, which will dominate real comparisons. Fix copy
+   and add an interim example.
+5. **Barclay's "published an overall grade only — no area-by-area
+   detail" misdescribes inspections.** No inspection type does that; a
+   2021 graded inspection necessarily had subgrades — the gap is in our
+   dataset. If it was an ungraded (s8) inspection, "Outstanding" is a
+   carried-forward grade and should say so. Fix: "We don't hold
+   area-by-area detail for this inspection", and distinguish graded vs
+   ungraded in the data model.
+
+## Should-fix
+
+6. Writing is teacher assessment, not a test — "national tests and
+   teacher assessments"; note TA caveat on the Writing strip.
+7. Verify renewed-framework wording against Ofsted's final toolkit:
+   likely "Needs attention" (not "Attention needed") and "Personal
+   development and well-being" (which otherwise collides with the
+   identically-named legacy judgement). Pin every label to the
+   published toolkit.
+8. "Expected standard" now means two things on one page (Ofsted area
+   rating vs KS2 measure) — disambiguate in tooltips.
+9. Disadvantaged row: DfE definition includes looked-after / previously
+   looked-after children, not just FSM6; benchmark labels inconsistent
+   across desktop/mobile; subgroup percentages need cohort sizes or a
+   volatility threshold before chips are attached.
+10. "Trend, last 7 years" spans ten years; sparklines render the COVID
+    gap as equal spacing (the exact defect the audit criticises) and
+    "Improved: 52% → 87%" endpoint-cherry-picks a volatile series.
+11. At-a-glance "Getting a place" uses different metrics per school
+    (Barclay is also oversubscribed on total preferences but shows a
+    green chip). Standardise on first-preference success %. Explain the
+    equal-preference rule; condition "living close by matters" on the
+    school's actual oversubscription criteria.
+12. "457 applications for 180 places" = total preferences at any rank,
+    not head-to-head applicants; lead with first preferences vs places.
+    Add offers-vs-final-intake (waiting lists/appeals) caveat.
+13. Elmhurst's subgrade list is likely missing Early years provision
+    (school has a nursery) — possible pipeline gap.
+14. "Ofsted rating" label is obsolete post-Sept-2024 — use "Latest
+    Ofsted inspection"; check whether Oct 2021 is the latest inspection
+    or merely the latest graded one.
+15. SEN: "EHCP plans" is redundant; 28% SEN support often indicates
+    resourced provision — add a note; England SEN-support ≈ 14%, not 13%.
+
+## Nice-to-have
+
+16. Consistent labelling of official DfE vs dataset-computed benchmarks
+    (and medians shouldn't be called averages inconsistently).
+17. England 2015/16 RWM (53%) exists in DfE publications — the null is
+    a dataset gap; source it or the England line looks broken.
+18. "1 in 4 first choices missed out" — actually more than 1 in 4.
+19. "1,273 of 1,260 places (full)" is over capacity; capacity figures
+    are often stale — say "at or above capacity".
+20. State the actual suppression rule (DfE: ≤5 pupils suppressed,
+    small numbers rounded) instead of "a handful".
+21. Spec §4.3 progress chips can't exist for displayed years: KS2
+    progress ended with 2022/23 (no KS1 baseline) and returns
+    ~2027/28 with the reception baseline. Make explicit in the spec.
+    IDACI (spec §4.5) is absent from mockups; if shipped, caveat it
+    describes pupils' neighbourhoods, not the school.
+22. Tooltips should give the official term "first preference" alongside
+    the plain-English "first choice".
+
+## Overall assessment (verbatim gist)
+
+The bones are genuinely good by education-data standards —
+England-average anchoring, explicit non-comparability messaging across
+Ofsted regimes, refusal to synthesise an overall grade, time-true
+x-axis, neutral FSM/EAL framing — better than most commercial
+school-comparison sites. But items 1–5 are outright factual errors or
+misdescriptions that a well-informed parent or Ofsted would catch;
+the admissions section needs the most conceptual work (equal
+preference, preferences-vs-applicants, offers-vs-intake). Fix 1–5
+before user testing; the rest fold into the planned PRs.
+
+---
+
+# Second-pass review (2026-07-12)
+
+Same reviewer, after the must-fixes and the new three-tier metric
+exposure model were applied.
+
+## Verification of first-pass must-fixes
+
+- **1 (COVID/2021/22): resolved.** Time-true axis, band covers only the
+  cancelled years, England 58.7% consistent with official figures,
+  dataset gaps break lines honestly; reading/maths England series all
+  match published figures; RWM ≤ min(subject) checks pass.
+- **2 (report-card count): resolved** — safeguarding excluded, spec §8.2.
+- **3 (offers derivation): resolved** — row removed, spec §8.3 bans it.
+- **4 (Ofsted timeline): resolved on desktop; mobile omits the interim
+  regime clause** (see finding 6).
+- **5 (Barclay explanation): resolved.**
+
+## New findings
+
+1. **Should-fix — scaled-score strip domain contradicts caption.**
+   Caption says "scaled scores run 80–120", strips render 100–120;
+   truncated domain exaggerates small gaps and below-100 averages
+   would fall off the edge. Render 80–120, or caption the 100–120
+   window honestly and define below-100 behaviour.
+2. **Should-fix — scaled-score England ticks (106/105/105) unsourced.**
+   Plausible but hand-entered; verify against DfE 2024/25 tables and
+   add loading official England scaled scores to the pipeline list
+   (absent from §8.1/§8.6).
+3. **Should-fix — "Writing" listed under "Higher standard" in the
+   picker.** Writing TA outcome is "greater depth" (GDS), never
+   "higher standard". Label "Writing — greater depth (teacher
+   assessment)"; tooltip the combined higher-standard composition.
+4. Nice — "grammar & punctuation" summary line drops "spelling" (GPS).
+5. Nice — science is teacher-assessed (no KS2 test since 2009) and
+   coarse; tooltip it like writing; reconsider its tier-2 slot.
+6. **Should-fix — mobile Ofsted copy skips the interim regime**
+   (Sept 2024–Nov 2025) that desktop explains. One clause fixes it.
+7. **Should-fix — benchmark provenance still inconsistent** (EAL
+   tooltip unsourced; FSM/disadvantaged chips vs tooltips use three
+   vocabularies; header note says all England averages are official).
+   Adopt one house style: official = "England average", computed =
+   "benchmark / typical state school (our dataset)". Also tighten EAL
+   definition to census wording ("first language known or believed to
+   be other than English").
+8. Nice — "community primaries" distance note attached to an academy
+   (Elmhurst); say "non-faith primaries" or condition on policy field.
+9. Nice — "Improving since 2022" → "since 2022/23".
+10. Nice — England chart tooltips show decimals; §7 mandates whole
+    percents.
+
+## Residual gaps not covered by spec §8
+
+11. Spec promises IDACI-in-words, Attendance section, and tier-2
+    gender/absence that the mockups never show — mark post-v1 or
+    demonstrate, so implementation scope is unambiguous.
+12. Add official England scaled-score averages to the pipeline task
+    list.
+13. Add the writing/greater-depth terminology rule to §8.7.
+
+## Verdict
+
+All must-fixes genuinely resolved; the tier model is conceptually
+sound ("no measure is lost", honest dataset-gap breaks, grouped
+picker). Remaining issues are contained: one internal contradiction
+(80–120 vs 100–120), one provenance inconsistency, one terminology
+error (writing/GDS). With findings 1–3 and 6–7 addressed, the data
+framing is fit to put in front of parents.

docs/superpowers/specs/2026-07-11-compare-screen-redesign-design.md

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+# Compare Screen Redesign — Audit & Design
+
+**Date:** 2026-07-11
+**Status:** Draft — awaiting review
+**Scope:** `/compare` page (nextjs-app), `/api/compare` endpoint (backend)
+
+## 1. Audit of the current screen
+
+The current compare page (`nextjs-app/components/ComparisonView.tsx`) is a
+single-metric analyst tool: a `<select>` with ~40 KS2/GCSE metrics, one
+line chart over time, and a year-by-year table — all for the one selected
+metric. Observed on production with 3 primary schools:
+
+**What works**
+
+- URL-shareable state (`?urns=…&metric=…`), native share sheet.
+- Phase tabs (primary/secondary) with sensible auto-detection.
+- Colour-coded school cards tied to chart series.
+- Metric descriptions from `/api/metrics` (single source of truth).
+
+**What doesn't**
+
+1. **Performance-only.** The database already holds Ofsted inspections,
+   admissions/oversubscription history, pupil characteristics (FSM/EAL),
+   SEN, deprivation (IDACI), finance, capacity, faith, gender, trust —
+   none of it reaches the compare screen. `/api/compare` returns only
+   `yearly_data` + minimal `school_info`, while `/api/schools/{urn}`
+   already returns all supplementary blocks.
+2. **One metric at a time.** A parent must know which of ~40 metrics
+   matters, select each in turn, and hold results in their head. There is
+   no side-by-side overview and no way to see two dimensions at once.
+3. **No benchmarks.** Numbers float without anchors: is 79% RWM good?
+   The DB has official national averages (`fact_ks2_national_averages`)
+   but the page never shows them.
+4. **Domain jargon untranslated.** "GPS Expected %", "Progress scores",
+   "RWM Combined" assume DfE literacy. The only plain-English help is one
+   note for progress scores.
+5. **Raw numbers, no judgement support.** 87.0% vs 92.0% vs 79.0% — the
+   page never says "all three are well above the England average of 62%",
+   which is the fact a parent actually needs.
+6. **Bugs/paper cuts observed:** the third school's series did not render
+   on the production chart despite table data (worth a separate fix);
+   the COVID gap (2018/19 → 2022/23) renders as equal spacing with no
+   annotation; table shows "87.0%" precision that implies false accuracy.
+
+## 2. Data inventory (available vs shown)
+
+| Domain | Source table | On detail page | On compare |
+|---|---|---|---|
+| KS2 attainment/progress | fact_ks2_performance | yes | **yes** (only thing shown) |
+| National averages | fact_ks2_national_averages | partial | no |
+| Ofsted (latest + subgrades + report-card fields) | fact_ofsted_inspection, dim_school | yes | no |
+| Admissions & oversubscription (multi-year) | fact_admissions | yes | no |
+| Pupil characteristics (FSM, EAL, gender split) | fact_pupil_characteristics | yes | no |
+| Context (SEN, disadvantaged, stability, absence) | fact_ks2_performance | via metric picker | buried in picker |
+| Deprivation (IDACI) | fact_deprivation | yes | no |
+| Finance (per-pupil spend) | fact_finance | yes | no |
+| School facts (capacity, faith, ages, trust, nursery, gender) | dim_school | yes | no |
+| Location/distance | dim_location | map | no |
+
+## 3. Design goals
+
+1. **Answer parent questions, in order:** Is it a good school (Ofsted)?
+   Do children do well there (academics vs England)? Will my child get a
+   place (admissions)? What is the school like (size, community, faith)?
+2. **Every number gets an anchor** — the England average, rendered as a
+   consistent visual tick, plus a plain-English chip
+   (Above / Close to / Below England average).
+3. **Plain English first, jargon on demand.** Labels are questions or
+   sentences ("Children reaching the expected standard in reading,
+   writing and maths"), codes/acronyms live in tooltips.
+4. **Scan whole-picture first, drill down second.** The single-metric
+   trend explorer survives, demoted to an "Explore trends" section at the
+   bottom rather than being the entire page.
+
+## 4. Proposed structure
+
+Columns = schools (max 4 visible on desktop, horizontal scroll beyond),
+rows = dimensions. Sticky compact school header keeps column identity
+while scrolling. Sections, in order:
+
+1. **At a glance** — verdict row per school: Ofsted badge, headline
+   attainment vs England (dot strip + chip), oversubscription chip,
+   size, distance (when a location is set).
+2. **Ofsted inspection** — must handle all three inspection regimes,
+   which will coexist in comparisons for years:
+   - **Legacy graded (pre-Sept 2024):** overall grade badge
+     (Outstanding/Good/Requires improvement/Inadequate). Subgrades,
+     where published, are rendered in the **same area-by-rating chip
+     list UX as report cards** (one row per judgement area, rating as
+     a chip) — one visual grammar for inspection detail across both
+     regimes. Where our dataset has no subgrades for an inspection,
+     say so honestly ("We don't hold area-by-area detail for this
+     inspection") and point to the school's Ofsted page — never claim
+     the inspection itself published no detail (graded inspections
+     always have subgrades; if it was ungraded, the grade is
+     carried forward and must be labelled as such).
+   - **Interim ungraded (Sept 2024 – Nov 2025):** parsed outcome
+     ("remains Good") shown as the effective grade, marked as such.
+   - **Renewed framework report card (from Nov 2025):** no overall
+     grade exists. Render the report card as an area-by-rating list
+     using Ofsted's 5-point scale (Exceptional / Strong standard /
+     Expected standard / Attention needed / Urgent improvement) across
+     the evaluation areas we model (`rc_inclusion`,
+     `rc_curriculum_teaching`, `rc_achievement`,
+     `rc_attendance_behaviour`, `rc_personal_development`,
+     `rc_leadership_governance`, `rc_early_years`, `rc_sixth_form`)
+     plus the separate safeguarding met/not-met flag. **At-a-glance
+     summary rule:** never an unlabelled colour strip — summarise by
+     counting areas per rating, best first ("5 areas Strong standard ·
+     3 areas Expected standard"), and always name any area rated
+     Attention needed or Urgent improvement explicitly (never fold
+     problems into a count), plus "Safeguarding not met" whenever that
+     flag is false. When everything is Expected standard or better,
+     add the reassurance line "No areas need attention".
+   When a comparison mixes regimes, show a one-line comparability note
+   ("Ofsted changed how it reports in Nov 2025 — a report card and an
+   older overall grade aren't directly comparable"). Never derive a
+   fake overall grade from report-card areas.
+3. **Academics (KS2)** — one dot-strip row per headline measure (RWM
+   expected, RWM higher, reading/writing/maths expected), each with the
+   England-average tick and per-school dots; copy must say "tests and
+   teacher assessments" (writing is TA, not a test). Progress scores
+   translated to Above/Average/Below chips (CI-based) — **but note KS2
+   progress measures ended with 2022/23** (no KS1 baseline afterwards)
+   and return only when the reception-baseline cohort reaches Y6
+   (~2027/28), so progress chips apply to historical years in the
+   trends explorer, not the headline view. Sparkline per school over
+   the full published period, with an honest gap for the cancelled
+   test years (2019/20–2020/21). Disadvantaged-pupils row under an
+   "Equity" subheading, always with cohort size shown and DfE's full
+   definition (FSM6 **or** looked-after/previously looked-after).
+4. **Getting a place** — oversubscription ratio as plain sentence
+   ("184 applications for 80 places"), first-preference success %, trend
+   vs last year, admissions policy.
+5. **Who goes there** — pupils on roll (vs capacity), boys/girls, FSM %,
+   EAL %, SEN support %, faith, ages, nursery, trust. *Post-v1:* IDACI
+   decile in words (needs a coverage check of `fact_deprivation` and
+   the neighbourhood-not-school caveat, §8.7).
+6. **Attendance** — *post-v1.* The KS2 test-day absence fields are the
+   only per-school absence data we hold; they're near-zero for most
+   schools and easy to misread as general attendance. Ship only if a
+   general-absence source lands.
+7. **Explore trends** (existing feature, collapsed) — metric picker +
+   multi-year line chart + table, with an added England-average
+   reference line and a COVID-gap annotation.
+
+**Metric exposure model (three tiers).** No measure from the current
+page is lost; they surface at three levels of prominence:
+- **Tier 1 — headline strips (always visible):** RWM expected,
+  reading/writing/maths expected, RWM higher standard.
+- **Tier 2 — "More measures" expansion inside Academics:** GPS and
+  science expected % (science labelled teacher-assessed), average
+  scaled scores (reading/maths/GPS, same dot-strip grammar showing
+  the 100–120 window of the 80–120 scale, widening below 100, with
+  the England tick) — one tap/click away, same visual language.
+  *Post-v1:* gender split and absence (see §4.6).
+- **Tier 3 — Explore trends:** the full grouped catalogue (the
+  current page's ~40 metrics, including equity and school-context
+  measures, and the GCSE set for secondary phase) drives the
+  year-by-year chart and table via the grouped metric picker.
+The tier assignment is a content decision per phase (secondary:
+Attainment 8, Progress 8 banding, grade 5+ English & maths as tier 1;
+EBacc and subject entries as tier 2).
+
+Finance (per-pupil spend) is deliberately deferred: low parent value,
+risk of misreading. Revisit later.
+
+**Mobile (design target — mobile first):** the desktop grid is the
+adaptation, not the other way round. On mobile the layout goes
+*measure-first*: each row is one measure with all schools listed under
+it (colour dot + short name + value + chip), so comparison never
+requires horizontal swiping between school cards. A sticky horizontal
+school-chip bar keeps identity and add/remove available while
+scrolling. Dot strips already read measure-first and carry over
+unchanged. The trend chart scrolls horizontally inside its container.
+
+## 5. Data strategy — existing dataset only
+
+Constraint (agreed 2026-07-11): use only data already in marts plus
+fields already present in the `raw` schema extracts we pull today.
+No new external sources.
+
+**Gaps in the mockup, resolved within this constraint:**
+
+| Mockup element | Resolution |
+|---|---|
+| England average for disadvantaged pupils | Compute from our own data: `stg_ees_ks2` already pivots the Disadvantaged breakdown per school; aggregate it (weighted by eligible pupils) into `fact_ks2_national_averages` or compute in the API. Label it "England average (state schools)". |
+| England context for FSM / EAL / SEN chips | Compute dataset-wide medians per phase, same pattern as `/api/national-averages` does for KS4. |
+| "Much larger than average" size label | Dataset median pupils-on-roll per phase. |
+| Ofsted link | We don't have deep links to the latest report, so always link to the school's Ofsted provider page, `https://reports.ofsted.gov.uk/provider/21/{urn}`, derived from URN (label it "the school's Ofsted page", not "the report"). |
+
+**Raw fields we already pull but don't store — promote to marts (one
+dbt/pipeline PR, no tap changes):**
+
+- `raw.ees_admissions`: 2nd/3rd preference applications and offers,
+  total-preference counts, cross-LA applications and offers → richer
+  "Getting a place" (e.g. "offers reached 2nd-choice families",
+  competition from outside the borough).
+- `raw.ees_ks2_attainment`: progress-measure confidence intervals and
+  "working towards" % → lets the Above/Average/Below progress chips be
+  statistically honest (band by CI overlap with 0, mirroring DfE
+  methodology) instead of thresholding the point estimate.
+- `raw.ees_ks4_performance` / `ees_ks4_info`: `progress8_banding`
+  (DfE's own plain-English "well above average … well below average"
+  label — exactly the chip we want for secondary), EBacc entry/APS,
+  grade-5+ English & maths, `attainment8_diffn`/`progress8_diffn`
+  (disadvantage gaps) → the secondary-phase version of the Academics
+  section.
+- `raw.ees_census`: young-carer % and the ethnicity breakdown →
+  optional "Who goes there" enrichment; hold for a later iteration
+  (presentation needs care), but the data requires no new extract.
+- `raw.ofsted_inspections` / tap-uk-ofsted: the `rc_*` report-card
+  columns exist in staging/marts but are stubbed `null` — the tap has a
+  TODO to map the report-card column names from the Ofsted MI file
+  (same monthly extract we already download; inspections from Nov 2025
+  onward carry them). This is the one promotion that needs a small tap
+  schema addition, and it's a prerequisite for the new-framework Ofsted
+  display above.
+
+Explicitly out (not in any current extract): school-level phonics,
+workforce/teacher data, per-school attendance beyond the KS2 test-day
+absence fields, Ofsted report-card documents themselves.
+
+## 6. API changes
+
+Extend `GET /api/compare` response per URN with the same supplementary
+blocks the detail endpoint already builds (`get_supplementary_data`):
+`ofsted`, `census`, `admissions` (+ `admissions_history`), `deprivation`,
+plus a top-level `national_averages` block for the latest year. Reuse the
+existing function; no new tables. Response stays backward-compatible
+(additive fields only). Add derived helper fields server-side or compute
+chips client-side from `national_averages` (client-side preferred — no
+schema churn).
+
+## 7. Accessibility & comprehension devices
+
+- Verdict chips are text + colour + position (never colour alone).
+- Every acronym has a tooltip using existing `MetricTooltip`.
+- "How to read this" one-liner at the top of each section.
+- Chart palette: coral `#e07256`, teal `#00949b`, purple `#8664c9`
+  (validated: lightness band, chroma, CVD separation, contrast — the
+  current `--chart-2/-4` tokens fail chroma/contrast checks and should
+  be nudged to these).
+- Numbers rounded to whole percents; England tick labelled on first use.
+
+## 8. Expert-review requirements
+
+An adversarial review by an education-data expert (full findings in
+`2026-07-11-compare-screen-expert-review.md`) was applied to the
+mockups on 2026-07-12. The following are binding requirements for
+implementation, beyond what the mockups can show:
+
+1. **Chart truthfulness:** KS2 tests were cancelled 2019/20–2020/21
+   only; 2021/22 results exist and must be loaded (school-level rows
+   and the 2015/16 national figure, 53%, are currently missing from
+   our dataset — pipeline task). Load official England averages for
+   GPS/science expected % and the scaled scores (reading/maths/GPS) —
+   the mockups' scaled-score ticks are indicative until then. Never
+   render missing years as if time were continuous.
+2. **Report-card summaries** count graded areas only — safeguarding is
+   a separate binary flag, never included in rating counts.
+3. **Admissions:** use the real preference-breakdown fields from
+   `raw.ees_admissions`; never derive "lower-preference offers" as
+   places − first-preference offers. Frame total applications as
+   "named on N forms" (any rank), lead with first-preference success,
+   and standardise at-a-glance chips on that one metric. Explain the
+   equal-preference rule; caveat offers vs final intake (waiting
+   lists/appeals); condition "distance decides" on the school's actual
+   oversubscription criteria where we have the admissions-policy field.
+4. **Ofsted:** overall grades ended September 2024 (report cards from
+   November 2025); the interim regime must be renderable. Distinguish
+   graded (s5) vs ungraded (s8) inspections and surface carried-forward
+   grades as such; "we don't hold the detail" is a statement about our
+   dataset, never about the inspection. Verify every scale/area label
+   against Ofsted's final published toolkit before launch (e.g. "Needs
+   attention" vs "Attention needed"; "Personal development and
+   well-being" vs the identically-named legacy judgement). Check
+   whether a school's latest inspection is merely its latest *graded*
+   one. Confirm Early years provision subgrades flow through the
+   pipeline for schools with nurseries.
+5. **Subgroup honesty:** disadvantaged-pupil percentages carry cohort
+   sizes and follow the DfE suppression rule (≤5 pupils suppressed);
+   state the rule verbatim in the footer.
+6. **Benchmark provenance:** official DfE figures and
+   dataset-computed benchmarks must be labelled distinctly and
+   consistently everywhere (a computed median is a "benchmark",
+   not an "England average").
+7. **Copy details:** "Latest Ofsted inspection" (not "Ofsted rating");
+   "EHC plans"; SEN-support benchmark ≈14%; high SEN share may
+   indicate resourced provision (say so neutrally); "at or above
+   capacity" rather than "full" (capacity data is often stale);
+   disambiguate Ofsted's "Expected standard" from the KS2 measure;
+   give official terms ("first preference") alongside plain English.
+   Writing has no "higher standard" — its TA outcome is "greater
+   depth (GDS)"; never list writing under a higher-standard group.
+   Science and writing are teacher-assessed and must be labelled as
+   such (no KS2 science test since 2009). House style for benchmark
+   provenance: official DfE figures say "England average"; computed
+   figures say "state-school average (computed from our dataset)" —
+   applied to every chip, tooltip, header note and section intro.
+   EAL uses the census wording: first language known or believed to
+   be other than English. If IDACI ships, caveat that it describes
+   pupils' home neighbourhoods, not the school.
+
+## 9. Rollout
+
+1. **PR 1 (backend):** extend `/api/compare` + tests.
+2. **PR 2 (frontend):** new compare layout behind the existing route;
+   e2e journey updated in the same PR (promotion gate).
+3. **Fix separately:** missing third series on the current chart.
+
+## 10. Open questions for review
+
+- Max schools: keep 10 in API but cap visible columns at 4 with scroll?
+- Should distance-from-home appear when the user searched by postcode
+  (data exists via `dim_location`)?
+- Keep finance out of v1? (Recommended: yes, out.)