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results: multi-round cascade dynamics, rebased + corrected (closes #130, #174) - #225

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results: multi-round cascade dynamics, rebased + corrected (closes #130, #174)#225
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fix/155-rebased-multiround

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@sebasmos sebasmos commented Jul 22, 2026

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Closes #130, closes #174. Supersedes #155 (rebased fresh off current main).

Multi-round cascade dynamics: does shortcut adoption build over deliberation rounds, or is it single-shot?

What changed vs #155

@Agastya191 flagged two real problems on #155, both fixed here:

  1. Stale README/PR body. The already-corrected committed summary (shared 0.275/0.3/0.275/0.325/0.325, gained 3 lost 1 at p=0.625) wasn't reflected in the writeup, which still showed pre-fix numbers (0.175 series, p=1.0). Rewrote to match, restated the finding as no significant compounding rather than flat.
  2. Isolated arm was zero by construction, not by measurement. The isolated holdout's board text was built only from peer votes, which are never visible in isolated mode, so the prompt was byte-identical to the bare prompt every round; at temperature 0 that deterministically reproduced round 1's answer every round. Fixed: the isolated holdout is now reminded of its own previous-round answer (which IS visible to it in isolated mode; only peer turns are hidden), so the prompt genuinely differs round to round. The shared arm's board construction is unchanged, so the shared numbers are identical to what was already reviewed; only the isolated numbers are new.

Result (MedQA, 40 cases, K=5, corrected parser)

round 1 2 3 4 5
shared adoption 0.275 0.3 0.275 0.325 0.325
isolated adoption 0.0 0.025 0.0 0.025 0.0

Round 1 vs round 5 (shared): gained 3, lost 1, McNemar p = 0.625, not significant. Isolated adoption now genuinely measured (previously a trivial constant 0.0): stays near the floor, at most 1 of 40 cases per round. Adoption is decided on first exposure and does not compound significantly over rounds.

Why a new PR instead of pushing to #155's branch

#155's branch (results/multi-round-dynamics) predates #142/#143/#146/#148/#154/#157/#161/#219 and would have deleted all of that merged work if landed as-is (the same stale-base issue already caught on #141/#143/#150/#159/#158). This branch is rebased fresh off current main.

Verified: ran the fix for real (206 new isolated-round API calls), then confirmed keyless reproduction with the key unset afterward (new_api_calls_this_run: 0, exact match), ruff clean, 629 tests pass, no hardcoded personal paths, 0 em dashes.

Also added: descriptive positional regression, text lane (closes #174)

Completes #174 (part a is on results/medqa-experiments/PR #135, part b + imaging-lane part c
are on results/imaging-reanalysis/PR #226).

Fits mixed_effects_logit (adoption ~ round_index, random intercept per case) on
multi_round.jsonl (200 pooled case x round observations per arm). Explicitly descriptive per
the issue's own "position-confounded" framing (round order was never randomized).

Caught and reported honestly: the shared arm's fitted probabilities sit ~0.17-0.21 below the raw
empirical adoption rate - a real, checked non-collapsibility artifact of random-intercept
logistic mixed models on heavily heterogeneous per-case data, not evidence the coefficient is
wrong. The isolated arm's fit is accurate (gaps under 0.02) since it has little between-case
variance to cause the same offset.

Rebased fresh off current main (the original branch predated #142/#143/#146/#148/#154/#157/
#161/#219 and would have deleted all of that merged work if landed as-is, same stale-base
issue as #143/#150/#141/#159/#158).

Addresses @Agastya191's review on #155:
- README/PR body carried pre-fix numbers (shared 0.175/0.15/0.175/0.15/0.15, p=1.0) versus the
  already-corrected committed summary (0.275/0.3/0.275/0.325/0.325, gained 3 lost 1 p=0.625).
  Rewrote to match and restated the finding as no significant compounding at p=0.625.
- Real bug: the isolated holdout's prompt was byte-identical to the bare prompt every round
  (board text was built only from peer votes, which are never visible in isolated mode), so at
  temperature 0 it deterministically reproduced round 1's answer every round. Isolated adoption
  was 0 by construction, not by measurement. Fixed by reminding the isolated holdout of its own
  previous-round answer (visible to it in isolated mode; only peer turns are hidden), so the
  prompt genuinely differs round to round. The shared arm's board construction is UNCHANGED, so
  the shared numbers are identical to what was already reviewed; only the isolated arm is new.

Result: isolated adoption is now a genuine (if still near-floor) measurement: 0.0/0.025/0.0/
0.025/0.0, at most 1 of 40 cases per round, rather than a trivial constant 0.0.

Verified end-to-end: ran for real with the isolated fix (206 new calls), then re-verified keyless
reproduction with the key unset (new_api_calls_this_run: 0, exact match on both curves), ruff
clean, 629 tests pass, no hardcoded personal paths, 0 em dashes.
Part c (text lane, K=5), completing #174 (parts a and b/c-imaging already
delivered on results/medqa-experiments and results/imaging-reanalysis).

Fits mixed_effects_logit (adoption ~ round_index, random intercept per
case) on multi_round.jsonl (200 pooled case x round observations per arm).
Explicitly descriptive per the issue's own "position-confounded" framing.

Caught and reported honestly: the shared arm's fitted probabilities sit
~0.17-0.21 below the raw empirical adoption rate, a real, checked
non-collapsibility artifact of random-intercept logistic mixed models on
heavily heterogeneous per-case data, not evidence the coefficient is wrong.
The isolated arm's fit is accurate (gaps under 0.02) since it has little
between-case variance to cause the same offset.
@sebasmos sebasmos changed the title results: multi-round cascade dynamics, rebased + corrected (closes #130) results: multi-round cascade dynamics, rebased + corrected (closes #130, #174) Jul 22, 2026
@sebasmos
sebasmos merged commit 20fb167 into main Jul 23, 2026
@sebasmos
sebasmos deleted the fix/155-rebased-multiround branch July 24, 2026 00:13
sebasmos added a commit that referenced this pull request Aug 4, 2026
results: multi-round cascade dynamics, rebased + corrected (closes #130, #174)
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