FA-12683 / Causal analysis data contracts / Member archive
Crossover carryover coding forgets actual prior exposure across untreated periods · case 03
A carryover covariate follows assigned treatment or disappears during an untreated period without a documented washout.
Case contract
Rows [subject,period,assigned,received,washed_out] have unique subject-period pairs. Treatments are A/B or None. The synthetic protocol defines carryover as the most recent actually received treatment since the last documented washout, persisting through untreated periods. Return sorted [subject,period,carryover] rows, with carryover evaluated before current receipt and after current washout. This is a categorical design encoding, not a pharmacokinetic claim.
Why this case matters
A deterministic synthetic study model isolates this data-contract defect; outputs alone establish no real-world causal identification.
One recorded failure
Sample boundary fixtureThis sample comes from the broken implementation of a controlled reproducer.
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| actual receipt overrides assignment | [["s", 3, null], ["s", 4, "A"]] | [["s", 3, null], ["s", 4, "B"]] | Failed |
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