diff --git a/backend/app/routers/study_tools.py b/backend/app/routers/study_tools.py
index 74ba6ce..33a757f 100644
--- a/backend/app/routers/study_tools.py
+++ b/backend/app/routers/study_tools.py
@@ -242,12 +242,6 @@ def _category_rollup(categories):
     return ancestry
 
 
-class CompletionWindow(BaseModel):
-    """How far back to count. Days rather than dates: "this month" and "all
-    time" are the questions people actually ask of their own progress."""
-    days: int | None = None
-
-
 @router.get("/completion")
 def completion(
     days: int | None = Query(None, ge=1, le=3650),
@@ -296,6 +290,64 @@ def completion(
     }
 
 
+def _split(rows) -> dict:
+    """Correct / incorrect / unanswered, with the percentage out of answered."""
+    correct = sum(1 for row in rows if row.user_answer and row.is_correct)
+    incorrect = sum(1 for row in rows if row.user_answer and not row.is_correct)
+    blank = sum(1 for row in rows if not row.user_answer)
+    answered = correct + incorrect
+    return {
+        "correct": correct,
+        "incorrect": incorrect,
+        "unanswered": blank,
+        "answered": answered,
+        "total": len(rows),
+        "percent_correct": round(100 * correct / answered, 1) if answered else None,
+    }
+
+
+@router.get("/answer-split")
+def answer_split(
+    db: Session = Depends(get_db),
+    user: User = Depends(get_current_user),
+):
+    """The same answers counted two ways.
+
+    *All attempts* is every answer ever given: it says how much work has been
+    done. *Latest attempt* keeps only the most recent answer to each question:
+    it says what is known now. A learner who got a question wrong in March and
+    right in September is at 50% by the first measure and 100% by the second,
+    and both are true statements about different questions.
+
+    Repetitions, course quizzes and expired attempts are left out, as
+    everywhere else that measures rather than counts practice.
+    """
+    rows = db.query(
+        AttemptAnswer.question_id, AttemptAnswer.is_correct, AttemptAnswer.user_answer,
+        QuizAttempt.id.label("attempt_id"), QuizAttempt.completed_at,
+    ).join(QuizAttempt, QuizAttempt.id == AttemptAnswer.attempt_id
+    ).join(Quiz, Quiz.id == QuizAttempt.quiz_id
+    ).filter(
+        QuizAttempt.user_id == user.id,
+        QuizAttempt.completed_at.isnot(None),
+        or_(QuizAttempt.expired == 0, QuizAttempt.expired.is_(None)),
+        Quiz.course_id.is_(None),
+        or_(Quiz.is_repetition == 0, Quiz.is_repetition.is_(None)),
+    ).order_by(QuizAttempt.completed_at.asc(), QuizAttempt.id.asc()).all()
+
+    # Ordered oldest first, so the last write per question is the latest one.
+    latest: dict[int, object] = {}
+    for row in rows:
+        latest[row.question_id] = row
+
+    return {
+        "all": _split(rows),
+        "latest": _split(list(latest.values())),
+        "attempts": len({row.attempt_id for row in rows}),
+        "unique_questions": len(latest),
+    }
+
+
 @router.get("/recommendations")
 def study_recommendations(
     group: Literal["articles", "disciplines", "systems"] = "disciplines",
diff --git a/backend/tests/test_study_tools.py b/backend/tests/test_study_tools.py
index ce5794b..d0d4b57 100644
--- a/backend/tests/test_study_tools.py
+++ b/backend/tests/test_study_tools.py
@@ -355,3 +355,42 @@ class CompletionTests(unittest.TestCase):
         self.assertIsNone(data['seconds_per_question'])
         self.assertEqual(data['seconds_total'], 0)
         self.assertGreater(data['bank_total'], 0)
+
+
+class AnswerSplitTests(CompletionTests):
+    """The same answers counted two ways: everything done, and what is known now."""
+
+    def split(self):
+        response = self.client.get('/study-tools/answer-split')
+        self.assertEqual(response.status_code, 200, response.text)
+        return response.json()
+
+    def test_getting_it_wrong_then_right_reads_differently_by_basis(self):
+        self.sat(1, False, ago_days=90, seconds=40)
+        self.sat(1, True, ago_days=1, seconds=30)
+
+        data = self.split()
+        self.assertEqual(data['attempts'], 2)
+        self.assertEqual(data['unique_questions'], 1)
+        # Half the work was wrong; what is known now is right.
+        self.assertEqual(data['all'], {
+            'correct': 1, 'incorrect': 1, 'unanswered': 0,
+            'answered': 2, 'total': 2, 'percent_correct': 50.0})
+        self.assertEqual(data['latest'], {
+            'correct': 1, 'incorrect': 0, 'unanswered': 0,
+            'answered': 1, 'total': 1, 'percent_correct': 100.0})
+
+    def test_a_blank_is_its_own_slice_and_not_a_wrong_answer(self):
+        self.sat(1, True, ago_days=1, seconds=20)
+        self.sat(2, False, ago_days=1, seconds=0, answered=False)
+        data = self.split()
+        self.assertEqual(data['all']['unanswered'], 1)
+        self.assertEqual(data['all']['incorrect'], 0)
+        self.assertEqual(data['all']['total'], 2)
+        self.assertEqual(data['all']['percent_correct'], 100.0)
+
+    def test_nothing_sat_yet(self):
+        data = self.split()
+        self.assertEqual(data['attempts'], 0)
+        self.assertEqual(data['unique_questions'], 0)
+        self.assertIsNone(data['all']['percent_correct'])
diff --git a/frontend/src/components/Donut.css b/frontend/src/components/Donut.css
new file mode 100644
index 0000000..124577d
--- /dev/null
+++ b/frontend/src/components/Donut.css
@@ -0,0 +1,13 @@
+/* The ring and the key beside it. Lives with the component so a page that
+   renders one does not have to know which stylesheet drew it. */
+.an-donut-wrap { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
+.an-donut { width: 150px; height: 150px; flex-shrink: 0; }
+.an-donut-figure { font-size: 22px; font-weight: 700; fill: var(--text); }
+.an-donut-label { font-size: 9px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; fill: var(--text-subtle); }
+.an-legend { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 7px; font-size: 0.85rem; }
+.an-legend li { display: flex; align-items: center; gap: 8px; }
+.an-legend i { width: 11px; height: 11px; border-radius: 50%; flex-shrink: 0; }
+.an-legend .is-right { background: var(--correct-fg); }
+.an-legend .is-wrong { background: var(--wrong-fg); }
+.an-legend .is-answered { background: var(--primary); }
+.an-legend .is-none { background: var(--border); }
diff --git a/frontend/src/components/Donut.jsx b/frontend/src/components/Donut.jsx
new file mode 100644
index 0000000..baf92f2
--- /dev/null
+++ b/frontend/src/components/Donut.jsx
@@ -0,0 +1,50 @@
+import './Donut.css'
+
+/**
+ * Correct / incorrect / unanswered as one ring.
+ *
+ * Shared, because a session and a lifetime are the same picture at different
+ * scales, and two drawings of it would eventually disagree.
+ *
+ * `answered` is for work that is not marked yet — an exam still running has no
+ * score, and a nought in the middle would read as one.
+ */
+export default function Donut({ correct, incorrect, answered = 0, skipped, graded = true }) {
+  const total = correct + incorrect + answered + skipped
+  if (!total) return null
+  const circumference = 2 * Math.PI * 54
+  const slice = (n) => (n / total) * circumference
+  let offset = 0
+  const arcs = [
+    { value: correct, colour: 'var(--correct-fg)' },
+    { value: incorrect, colour: 'var(--wrong-fg)' },
+    { value: answered, colour: 'var(--primary)' },
+    { value: skipped, colour: 'var(--border)' },
+  ]
+  const label = graded
+    ? `${correct} correct, ${incorrect} incorrect, ${skipped} unanswered`
+    : `${answered} answered, ${skipped} unanswered — not marked yet`
+  return (
+    <svg className="an-donut" viewBox="0 0 140 140" role="img" aria-label={label}>
+      {arcs.map((arc, i) => {
+        const length = slice(arc.value)
+        const dash = `${length} ${circumference - length}`
+        const node = (
+          <circle key={i} cx="70" cy="70" r="54" fill="none" stroke={arc.colour}
+            strokeWidth="16" strokeDasharray={dash} strokeDashoffset={-offset}
+            transform="rotate(-90 70 70)" />
+        )
+        offset += length
+        return node
+      })}
+      {/* A percentage here would be a score, and an exam still running has
+          none. It says how far through it is instead. */}
+      <text x="70" y="68" textAnchor="middle" className="an-donut-figure">
+        {graded ? `${Math.round((correct / total) * 100)}%` : `${answered}/${total}`}
+      </text>
+      <text x="70" y="86" textAnchor="middle" className="an-donut-label">
+        {graded ? 'correct' : 'answered'}
+      </text>
+    </svg>
+  )
+}
diff --git a/frontend/src/pages/AnalysisPage.css b/frontend/src/pages/AnalysisPage.css
index 017affb..d126607 100644
--- a/frontend/src/pages/AnalysisPage.css
+++ b/frontend/src/pages/AnalysisPage.css
@@ -140,3 +140,28 @@
 }
 .an-completion-grid .an-stat { background: var(--card-bg); padding: 18px 14px; }
 .an-stat-of { font-size: 0.9rem; color: var(--text-muted); font-weight: 400; }
+
+/* ── The two panels above the category table ──────────────────────────
+   Completion says how much has been done; Analysis says how it went. They
+   read together, so they sit side by side until there is no room. */
+.an-perf-top {
+  display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
+  gap: 18px; align-items: start;
+}
+.an-perf-top .an-completion { margin: 24px 0 0; }
+.an-split-card {
+  margin-top: 24px; padding: 16px 18px 18px;
+  border: 1px solid var(--border); border-radius: 12px; background: var(--card-bg);
+}
+.an-split-card .an-basis { margin-top: 14px; }
+.an-basis-tabs { display: flex; gap: 4px; background: var(--surface-2, var(--border)); padding: 3px; border-radius: 9px; }
+.an-basis-tabs button {
+  border: 0; background: none; color: var(--text-muted); cursor: pointer;
+  font: inherit; font-size: 0.8rem; padding: 6px 11px; border-radius: 7px;
+}
+.an-basis-tabs button.is-on { background: var(--card-bg); color: var(--text); font-weight: 600; }
+
+@media (max-width: 900px) {
+  .an-perf-top { grid-template-columns: minmax(0, 1fr); }
+  .an-split-card { margin-top: 0; }
+}
diff --git a/frontend/src/pages/AnalysisPage.jsx b/frontend/src/pages/AnalysisPage.jsx
index 1a34e2f..de164b2 100644
--- a/frontend/src/pages/AnalysisPage.jsx
+++ b/frontend/src/pages/AnalysisPage.jsx
@@ -2,6 +2,7 @@ import { useState, useEffect, useCallback } from 'react'
 import { Link, useNavigate } from 'react-router-dom'
 import api from '../api/client'
 import CategoryPerformance from '../components/CategoryPerformance'
+import Donut from '../components/Donut'
 import AnalysisShell from '../components/AnalysisShell'
 import './AnalysisPage.css'
 
@@ -92,6 +93,78 @@ function Completion() {
   )
 }
 
+const BASES = [
+  { key: 'all', label: 'All attempts' },
+  { key: 'latest', label: 'Latest attempt' },
+]
+
+/**
+ * The same answers counted two ways.
+ *
+ * All attempts is every answer ever given — how much work has been done.
+ * Latest attempt keeps only the most recent answer to each question — what is
+ * known now. A question got wrong in March and right in September is 50% by
+ * one measure and 100% by the other, and neither figure is a lie.
+ */
+function AnswerSplit() {
+  const [basis, setBasis] = useState('all')
+  const [data, setData] = useState(null)
+  const [error, setError] = useState('')
+
+  useEffect(() => {
+    let live = true
+    api.get('/study-tools/answer-split')
+      .then(res => { if (live) setData(res.data) })
+      .catch(() => { if (live) setError('Could not load your answers') })
+    return () => { live = false }
+  }, [])
+
+  const split = data?.[basis]
+
+  return (
+    <section className="an-card an-split-card">
+      <div className="an-completion-head">
+        <h2>Analysis</h2>
+        <div className="an-basis-tabs" role="tablist" aria-label="Which answers to count">
+          {BASES.map(option => (
+            <button key={option.key} type="button" role="tab"
+              aria-selected={basis === option.key}
+              className={basis === option.key ? 'is-on' : ''}
+              onClick={() => setBasis(option.key)}>{option.label}</button>
+          ))}
+        </div>
+      </div>
+
+      {error ? <p className="an-empty" role="alert">{error}</p>
+        : !split ? <p className="an-empty">Loading…</p>
+        : split.total === 0 ? (
+          <p className="an-empty">
+            Nothing sat yet. Answer some questions and this fills in.
+          </p>
+        ) : (
+          <>
+            <div className="an-donut-wrap">
+              <Donut correct={split.correct} incorrect={split.incorrect}
+                skipped={split.unanswered} />
+              <ul className="an-legend">
+                <li><i className="is-right" />{split.correct} correct</li>
+                <li><i className="is-wrong" />{split.incorrect} incorrect</li>
+                <li><i className="is-none" />{split.unanswered} unanswered</li>
+              </ul>
+            </div>
+            <p className="an-basis">
+              {basis === 'all'
+                ? `${data.attempts} session${data.attempts === 1 ? '' : 's'}, ${data.unique_questions} unique question${data.unique_questions === 1 ? '' : 's'}.`
+                : `Your most recent answer to each of ${data.unique_questions} question${data.unique_questions === 1 ? '' : 's'}.`}
+              {' '}Unanswered questions are not counted as wrong: the percentage
+              is out of what you answered.
+            </p>
+          </>
+        )}
+    </section>
+  )
+}
+
 function FocusRow({ row, onPractise }) {
   const [open, setOpen] = useState(false)
   const coverageLabel = `${row.seen_questions}/${row.available}`
@@ -308,7 +381,10 @@ export default function AnalysisPage() {
             </>
           ) : (
             <>
-              <Completion />
+              <div className="an-perf-top">
+                <Completion />
+                <AnswerSplit />
+              </div>
               <CategoryPerformance />
             </>
           )}
diff --git a/frontend/src/pages/AnalysisPage.test.jsx b/frontend/src/pages/AnalysisPage.test.jsx
index e59871e..e6d24ba 100644
--- a/frontend/src/pages/AnalysisPage.test.jsx
+++ b/frontend/src/pages/AnalysisPage.test.jsx
@@ -111,3 +111,40 @@ it('reports completion over a window, and changes the window', async () => {
   await waitFor(() => expect(within(panel).getByText('400')).toBeInTheDocument())
   expect(api.get).toHaveBeenCalledWith('/study-tools/completion', { params: {} })
 })
+
+it('counts the same answers two ways: all attempts and the latest one', async () => {
+  const split = {
+    all: { correct: 1, incorrect: 1, unanswered: 0, answered: 2, total: 2, percent_correct: 50.0 },
+    latest: { correct: 1, incorrect: 0, unanswered: 0, answered: 1, total: 1, percent_correct: 100.0 },
+    attempts: 2, unique_questions: 1,
+  }
+  api.get.mockImplementation(url =>
+    Promise.resolve({ data: url === '/study-tools/answer-split' ? split : payload() }))
+
+  render(<MemoryRouter><AnalysisPage /></MemoryRouter>)
+  await userEvent.click(await screen.findByRole('tab', { name: 'Performance' }))
+
+  const panel = (await screen.findByText('Analysis')).closest('.an-split-card')
+  expect(within(panel).getByText('1 correct')).toBeInTheDocument()
+  expect(within(panel).getByText('1 incorrect')).toBeInTheDocument()
+  expect(within(panel).getByText(/2 sessions, 1 unique question\./)).toBeInTheDocument()
+
+  // Wrong in March, right in September: the latest answer is the one that says
+  // what is known now.
+  await userEvent.click(within(panel).getByRole('tab', { name: 'Latest attempt' }))
+  expect(within(panel).getByText('0 incorrect')).toBeInTheDocument()
+  expect(within(panel).getByText(/most recent answer to each of 1 question/)).toBeInTheDocument()
+})
+
+it('says plainly when nothing has been sat', async () => {
+  const empty = {
+    all: { correct: 0, incorrect: 0, unanswered: 0, answered: 0, total: 0, percent_correct: null },
+    latest: { correct: 0, incorrect: 0, unanswered: 0, answered: 0, total: 0, percent_correct: null },
+    attempts: 0, unique_questions: 0,
+  }
+  api.get.mockImplementation(url =>
+    Promise.resolve({ data: url === '/study-tools/answer-split' ? empty : payload() }))
+  render(<MemoryRouter><AnalysisPage /></MemoryRouter>)
+  await userEvent.click(await screen.findByRole('tab', { name: 'Performance' }))
+  expect(await screen.findByText(/Nothing sat yet/)).toBeInTheDocument()
+})
diff --git a/frontend/src/pages/AnalysisSessionPage.css b/frontend/src/pages/AnalysisSessionPage.css
index 4f0c5cd..84a80e6 100644
--- a/frontend/src/pages/AnalysisSessionPage.css
+++ b/frontend/src/pages/AnalysisSessionPage.css
@@ -19,16 +19,6 @@
 .an-card h2 { margin: 0 0 12px; font-size: 1rem; }
 .an-note { margin: 0; font-size: 0.85rem; color: var(--text-muted); }
 
-.an-donut-wrap { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
-.an-donut { width: 150px; height: 150px; flex-shrink: 0; }
-.an-donut-figure { font-size: 22px; font-weight: 700; fill: var(--text); }
-.an-donut-label { font-size: 9px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; fill: var(--text-subtle); }
-.an-legend { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 7px; font-size: 0.85rem; }
-.an-legend li { display: flex; align-items: center; gap: 8px; }
-.an-legend i { width: 11px; height: 11px; border-radius: 50%; }
-.an-legend .is-right { background: var(--correct-fg); }
-.an-legend .is-wrong { background: var(--wrong-fg); }
-.an-legend .is-none { background: var(--border); }
 
 .an-recs { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 9px; }
 .an-recs li { display: grid; grid-template-columns: 1fr 90px 46px; align-items: center; gap: 10px; font-size: 0.85rem; }
@@ -161,5 +151,4 @@ td.an-col-q { display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px; }
 }
 
 /* Answered, but not yet marked — an exam that is still running. */
-.an-legend .is-answered { background: var(--primary); }
 .an-status.is-answered { background: var(--option-sel-bg); color: var(--primary); }
diff --git a/frontend/src/pages/AnalysisSessionPage.jsx b/frontend/src/pages/AnalysisSessionPage.jsx
index 6e43ae7..656675d 100644
--- a/frontend/src/pages/AnalysisSessionPage.jsx
+++ b/frontend/src/pages/AnalysisSessionPage.jsx
@@ -1,6 +1,7 @@
 import { useCallback, useEffect, useMemo, useState } from 'react'
 import { Link, useNavigate, useParams } from 'react-router-dom'
 import AnalysisShell from '../components/AnalysisShell'
+import Donut from '../components/Donut'
 import RepeatSession from '../components/RepeatSession'
 import api from '../api/client'
 import './AnalysisSessionPage.css'
@@ -19,48 +20,6 @@ const hours = (seconds) => {
   return h ? `${h}h ${String(m).padStart(2, '0')}m` : `${m}m`
 }
 
-/** Correct / incorrect / unanswered as one ring. */
-function Donut({ correct, incorrect, answered = 0, skipped, graded = true }) {
-  const total = correct + incorrect + answered + skipped
-  if (!total) return null
-  const circumference = 2 * Math.PI * 54
-  const slice = (n) => (n / total) * circumference
-  let offset = 0
-  const arcs = [
-    { value: correct, colour: 'var(--correct-fg)' },
-    { value: incorrect, colour: 'var(--wrong-fg)' },
-    // Neither right nor wrong yet: an exam that is still running is not marked.
-    { value: answered, colour: 'var(--primary)' },
-    { value: skipped, colour: 'var(--border)' },
-  ]
-  const label = graded
-    ? `${correct} correct, ${incorrect} incorrect, ${skipped} unanswered`
-    : `${answered} answered, ${skipped} unanswered — not marked yet`
-  return (
-    <svg className="an-donut" viewBox="0 0 140 140" role="img" aria-label={label}>
-      {arcs.map((arc, i) => {
-        const length = slice(arc.value)
-        const dash = `${length} ${circumference - length}`
-        const node = (
-          <circle key={i} cx="70" cy="70" r="54" fill="none" stroke={arc.colour}
-            strokeWidth="16" strokeDasharray={dash} strokeDashoffset={-offset}
-            transform="rotate(-90 70 70)" />
-        )
-        offset += length
-        return node
-      })}
-      {/* A percentage here would be a score, and an exam still running has
-          none. It says how far through it is instead. */}
-      <text x="70" y="68" textAnchor="middle" className="an-donut-figure">
-        {graded ? `${Math.round((correct / total) * 100)}%` : `${answered}/${total}`}
-      </text>
-      <text x="70" y="86" textAnchor="middle" className="an-donut-label">
-        {graded ? 'correct' : 'answered'}
-      </text>
-    </svg>
-  )
-}
-
 const SORTS = {
   position: (a, b) => a.position - b.position,
   slowest: (a, b) => (b.seconds_spent ?? -1) - (a.seconds_spent ?? -1),