A-01 v1.2 · Understanding probability and the house edge
In use · permanently lockedThe read-only measurement instrument used by the Q2 2026 cohort. It contains question wording and scoring keys, but no participant names, answers, account codes or individual scores.
This version cannot be edited, reopened, reordered or replaced
Baseline and endline must use the same ruler. Once the first response was recorded against v1.2, the version became immutable for every role, including System admin. Any wording change belongs in a new draft for a future cohort. This page therefore has no edit, duplicate, unlock, delete or publish controls.
Version record
A-01 · v1.2| Instrument type | Knowledge assessment · baseline and endline |
|---|---|
| Written by | Sam Okafor · Content admin |
| Clinical sign-off | Dr Alice Brennan · 24 March 2026 |
| Locked by | Priya Raman · Impact analyst · 31 March 2026, 09:14 AEST |
| Locked for | Q2 2026 pilot cohort |
| Replaces | A-01 v1.1 · internal trial only |
| Content checksum | sha256: 9b24…e813 |
| Unlock date | None · used versions stay locked permanently |
Status and measurement use
- Baseline: 64 sittings recorded at the end of onboarding.
- Endline: 41 sittings recorded; 23 cohort members are not yet due or did not take the voluntary follow-up.
- Pairing rule: METRIC-01 pairs only baseline and endline records carrying this exact version identifier.
- Scoring: one mark per question, no timer and no answer feedback after baseline.
- Reward: the assessment schema has no token or benefit field at all.
Counts are aggregate. This page cannot open the records behind them and cannot reveal who completed, skipped or declined an assessment.
Access boundary
R09 can inspect the ruler used to produce METRIC-01. That does not grant access to the people measured by it.
- No names, email addresses or account identifiers.
- No individual answers or individual scores.
- No link from a count to a participant record.
- No route to edit content or clinical approval.
Small-group suppression still applies on Pilot metrics; reading an instrument never bypasses it.
Retention rule
The immutable instrument and its version/audit metadata are retained with every closed reporting period that used them. This preserves the ability to verify what participants were asked without retaining participant answers on this page.
If the organisation's approved research-retention schedule changes, the schedule is recorded prospectively. It does not rewrite a closed snapshot or silently detach the instrument from a report already issued.
Sample questions from the locked instrument
Shown exactly as stored in v1.2, with the scoring key needed to audit the instrument. Correct answers are never sent to the participant while an assessment is in progress and are not shown after baseline.
| # | Code | Question and options | Construct | Scoring key |
|---|---|---|---|---|
| 1 | B-01 | A market is priced at 2.00. What probability does that price imply? A. 20% · B. 50% · C. 100% · D. It depends on the sport |
Odds and probability | B · 50% |
| 4 | B-04 | Two sides of the same match are priced at 2.10 and 1.75. Add the two implied
probabilities together. What is the total? A. Exactly 100% · B. About 105% · C. About 95% · D. It cannot be worked out |
Recognising the margin | B · 104.8% |
| 7 | B-07 | What is the house edge, and where does it sit in the odds you are shown? A. A withdrawal fee · B. Built into the price · C. Charged only on wins · D. A government-set rate |
Recognising the house edge | B |
| 11 | B-11 | After nine reds in a row, how do the chances of black on the tenth spin change? A. They rise · B. They fall · C. They do not change · D. They depend on the table |
Gambler's fallacy | C · no change |
| 14 | B-14 | If you double your stake after every loss, what happens to your long-run
expectation? A. It turns positive · B. It stays negative · C. It becomes zero · D. It depends on the streak |
Chasing losses | B |
| 20 | B-20 | What is the only reliable way to reduce what a priced market costs someone over
time? A. Shorter odds · B. Bet more often · C. Stake less or not at all · D. Wait for a losing run to end |
Applying the maths | C |
Append-only audit history
Every transition is retained. A correction creates a new event or a new version; no row below can be overwritten.
| When | Event | Actor | Evidence |
|---|---|---|---|
| 18/03/2026 14:20 | v1.2 draft created from v1.1 | Sam Okafor · R04 | EV-A01-118 |
| 24/03/2026 16:42 | Clinical review signed | Dr Alice Brennan · R05 | EV-A01-126 |
| 31/03/2026 09:14 | Locked for Q2 2026 | Priya Raman · R09 | EV-A01-131 |
| 01/04/2026 08:00 | First baseline recorded; permanent lock verified | System | EV-A01-132 |
| 31/07/2026 23:59 | Scheduled for the Q2 snapshot after period close | System | PS-2026-Q2 · not generated |
Trace this instrument into reporting
The chain stays inspectable without exposing a participant: A-01 v1.2 defines the ruler → the open Q2 period currently stores provisional aggregates and this version identifier → after 31 July, the generated locked snapshot will become the only source for the funding report.