fix(compare): expert should-fixes S1-S4, S6 — banded chips, P8 reason, KS4 gap caption, all-through framing, cohort sizes

S1: first-choice chip banded (More than half / About 1 in 3 / Over 1 in 4
missed out) so a 44%-offered grammar isn't understated by half.
S2: Progress 8 explains its absence for 2024/25+ cohorts (no KS2 baseline,
COVID) instead of a bare 'No data'.
S3: KS4 trend charts get their own honest gap caption (2019/20-2020/21
unpublished; later years not in our dataset yet); y-axis 'Value'→'Score';
buildCompareChart exposes englandOnlyYears.
S4: all-through schools labelled in chips, rail caption says 'N schools ·
<phase> view' for mixed baskets, whole-school roll no longer judged
against the single-phase median, community section carries an all-ages
caveat.
S6 (spec §8.5): disadvantaged attainment shows the cohort behind it
('of ~50 disadvantaged pupils').

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

nextjs-app/components/ComparisonChart.tsx

@@ -38,13 +38,15 @@ interface ComparisonChartProps {
   /** Official England figure per academic year for this metric — renders a
    * dashed grey reference line when provided. */
   nationalByYear?: Record<number, number | null | undefined>;
+  /** KS4 metrics get a different (honest) gap caption than KS2. */
+  isSecondary?: boolean;
 }
 
 // One shape per basket slot (MAX_SCHOOLS = 5) — secondary encoding so
 // converging lines stay tellable apart without relying on hue alone.
 const POINT_STYLES: PointStyle[] = ['circle', 'triangle', 'rect', 'rectRot', 'star'];
 
-export function ComparisonChart({ comparisonData, schools, metric, metricLabel, nationalByYear }: ComparisonChartProps) {
+export function ComparisonChart({ comparisonData, schools, metric, metricLabel, nationalByYear, isSecondary = false }: ComparisonChartProps) {
   const isMobile = useIsMobile();
   const [focusedUrn, setFocusedUrn] = useState<number | null>(null);
 
@@ -168,7 +170,7 @@ export function ComparisonChart({ comparisonData, schools, metric, metricLabel,
         display: true,
         title: {
           display: !isMobile,
-          text: kind === 'percentage' ? 'Percentage (%)' : kind === 'progress' ? 'Progress Score' : 'Value',
+          text: kind === 'percentage' ? 'Percentage (%)' : kind === 'progress' ? 'Progress Score' : 'Score',
           font: {
             size: 12,
             weight: 'bold',
@@ -240,11 +242,23 @@ export function ComparisonChart({ comparisonData, schools, metric, metricLabel,
       <div className={styles.canvasBox}>
         <Line data={chartData} options={options} aria-label={`${metricLabel} comparison chart`} />
       </div>
-      {built.showUnpublished202122Note && (
+      {isSecondary && built.englandOnlyYears.length > 0 ? (
+        // KS4's honest story differs from KS2's: 2019/20–2020/21 school-level
+        // GCSE results weren't published (COVID grading); later years WERE
+        // published by DfE but aren't in our dataset yet.
         <p className={styles.chartNote}>
-          No national tests were held in 2019/20 and 2020/21 (COVID), and DfE didn&apos;t publish
-          school-level figures for 2021/22 — the England average is shown for that year.
+          School-level GCSE figures for 2019/20 and 2020/21 weren&apos;t published (COVID
+          grading), and more recent years aren&apos;t in our dataset yet where lines break — the
+          England average is shown where available.
         </p>
+      ) : (
+        !isSecondary &&
+        built.showUnpublished202122Note && (
+          <p className={styles.chartNote}>
+            No national tests were held in 2019/20 and 2020/21 (COVID), and DfE didn&apos;t publish
+            school-level figures for 2021/22 — the England average is shown for that year.
+          </p>
+        )
       )}
     </div>
   );

nextjs-app/components/ComparisonView.tsx

@@ -365,12 +365,18 @@ export function ComparisonView({
             style={{ '--school-count': activeSchools.length } as CSSProperties}
             aria-label="Schools in this comparison"
           >
-            {/* Fills the 200px label rail on desktop (hidden on mobile). */}
+            {/* Fills the 200px label rail on desktop (hidden on mobile).
+                All-through schools must not be miscounted as "primary
+                schools"/"secondary schools" — mixed baskets get "· primary
+                view" phrasing instead. */}
             <div className={styles.barCaption}>
               <span className={styles.barCaptionEyebrow}>Comparing</span>
               <span className={styles.barCaptionCount}>
-                {activeSchools.length} {comparePhase} school
-                {activeSchools.length === 1 ? '' : 's'}
+                {activeSchools.every((sch) =>
+                  sch.phase?.toLowerCase().includes(comparePhase),
+                )
+                  ? `${activeSchools.length} ${comparePhase} school${activeSchools.length === 1 ? '' : 's'}`
+                  : `${activeSchools.length} schools · ${comparePhase} view`}
               </span>
             </div>
             {activeSchools.map((school, index) => (
@@ -390,7 +396,13 @@ export function ComparisonView({
                     <span className={styles.chipNameShort}>{shortName(school.school_name)}</span>
                   </a>
                   <span className={styles.chipMeta}>
-                    {[school.local_authority, school.school_type].filter(Boolean).join(' · ')}
+                    {[
+                      /all.?through/i.test(school.phase ?? '') ? 'All-through' : null,
+                      school.local_authority,
+                      school.school_type,
+                    ]
+                      .filter(Boolean)
+                      .join(' · ')}
                   </span>
                 </span>
                 <button

nextjs-app/components/compare/CompareAcademics.tsx

@@ -148,6 +148,15 @@ export function CompareAcademics({
       }
       return null;
     });
+    // DfE stopped publishing Progress 8 from 2024/25: those GCSE year groups
+    // sat no KS2 tests (COVID), so there is no baseline to measure progress
+    // from. A bare "No data" reads as a gap on our side — say why.
+    const latestYear = urns.reduce((max, urn) => {
+      const rows = data[String(urn)]?.yearly_data ?? [];
+      const y = rows.length ? Math.trunc(rows[rows.length - 1].year) : 0;
+      return Math.max(max, y);
+    }, 0);
+    const p8NotPublished = latestYear >= 202425;
     const grade5 = latestValues(data, urns, 'english_maths_strong_pass_pct');
     const ebacc = latestValues(data, urns, 'ebacc_entry_pct');
     const att8Anchor = nationalAverages?.secondary?.attainment_8_score;
@@ -189,6 +198,11 @@ export function CompareAcademics({
                 >
                   {banding[i]}
                 </Chip>
+              ) : p8NotPublished ? (
+                <span className={s.small}>
+                  Not published — this GCSE year group sat no KS2 tests (COVID), so DfE has no
+                  baseline to measure progress from
+                </span>
               ) : (
                 <span className={s.small}>No data</span>
               )}
@@ -218,6 +232,18 @@ export function CompareAcademics({
   const national = nationalAverages?.primary;
   const disadvantaged = latestValues(data, urns, 'rwm_expected_disadvantaged_pct');
   const disadvantagedAnchor = benchmarks?.primary?.disadvantaged_rwm_expected_pct ?? null;
+  // Cohort size behind the disadvantaged figure (spec §8.5): these are small
+  // groups where single pupils move the percentage — show roughly how many
+  // pupils the figure rests on.
+  const eligible = latestValues(data, urns, 'eligible_pupils');
+  const disadvantagedShare = latestValues(data, urns, 'disadvantaged_pct');
+  const cohorts = urns.map((_, i) => {
+    const n = eligible[i];
+    const share = disadvantagedShare[i];
+    if (n == null || share == null) return null;
+    const cohort = Math.round((n * share) / 100);
+    return cohort > 0 ? cohort : null;
+  });
 
   return (
     <Section
@@ -270,6 +296,9 @@ export function CompareAcademics({
                     <span className={s.big} style={{ fontSize: '1.1rem' }}>
                       {Math.round(value)}%
                     </span>{' '}
+                    {cohorts[i] != null && (
+                      <span className={s.small}>of ~{cohorts[i]} disadvantaged pupils</span>
+                    )}{' '}
                     {disadvantagedAnchor != null && (
                       <Chip tone={verdict(value, disadvantagedAnchor, 5) === 'below' ? 'warn' : 'good'}>
                         {verdict(value, disadvantagedAnchor, 5) === 'above' &&

nextjs-app/components/compare/CompareAtAGlance.tsx

@@ -170,8 +170,14 @@ export function CompareAtAGlance({
         {schools.map((school, i) => {
           const census = data[String(school.urn)]?.census;
           const pupils = census?.total_pupils ?? school.total_pupils ?? null;
+          // An all-through school's roll covers every age group, so judging
+          // it against the single-phase median ("Much larger than average")
+          // is meaningless — label the roll honestly instead.
+          const isAllThrough = /all.?through/i.test(school.phase ?? '');
           let sizeNote: string | null = null;
-          if (pupils != null && medianPupils != null) {
+          if (isAllThrough) {
+            sizeNote = 'Whole-school roll (all-through, all ages)';
+          } else if (pupils != null && medianPupils != null) {
             if (pupils >= medianPupils * 1.5) sizeNote = 'Much larger than average';
             else if (pupils >= medianPupils * 1.1) sizeNote = 'Larger than average';
             else if (pupils <= medianPupils * 0.66) sizeNote = 'Much smaller than average';

nextjs-app/components/compare/CompareCommunity.tsx

@@ -48,10 +48,25 @@ export function CompareCommunity({
     );
   };
 
+  const anyAllThrough = schools.some((school) => /all.?through/i.test(school.phase ?? ''));
+
   return (
     <Section
       title="Who goes there"
-      how="The school's community, from the latest school census. State-school averages are computed from our dataset and shown for context — there's no “right” number here."
+      how={
+        <>
+          The school&apos;s community, from the latest school census. State-school averages are
+          computed from our dataset and shown for context — there&apos;s no &ldquo;right&rdquo;
+          number here.
+          {anyAllThrough && (
+            <>
+              {' '}
+              For all-through schools these figures cover the whole school, all ages — not just
+              the {isSecondary ? 'secondary' : 'primary'} phase.
+            </>
+          )}
+        </>
+      }
     >
       <SectionGrid schools={schools}>
         <Measure label="Pupils on roll">

nextjs-app/components/compare/TrendsExplorer.tsx

@@ -119,6 +119,7 @@ export function TrendsExplorer({
               metric={metric}
               metricLabel={metricLabel}
               nationalByYear={nationalByYear}
+              isSecondary={!isPrimaryPhase}
             />
           </div>
         </div>