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Prove both on total bases -- and find that my own fix destroyed the backtest

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Nothing passed. Nothing promoted. Counter byte-identical.

THE BLOCKER, which is the real finding. statcast_aggregates is upserted in
place and holds exactly one as-of date. Yesterday's skill backtest was honest
only by accident: the nightly refresh was unreachable code, so the profiles
sat frozen at 2026-07-21 -- before the settled window. Repairing that cron was
right for production and it refreshed them to today, destroying every prior
version. Scoring a 2026-07-25 game now uses a season aggregate that contains
that game. Point-in-time validation is structurally impossible from that
table, so every number in this run is contaminated and directional, and none
of it is a gate verdict.

Fixed forward: statcast_history retains a dated snapshot on every refresh, so
point-in-time becomes "as_of_date < game_date, most recent". Retention is
best-effort and cannot fail the refresh; both properties are unit-tested. It
has one day of data, which is not yet a window.

SOLO BASELINE, n=383, Bonferroni across 12 tests (alpha 0.00417): nothing
passes. hard_hit_pct is closest at marginal r 0.135 with p 0.0080, failing
both the 0.15 effect bar and the corrected alpha. And it drifted DOWN from
0.153 at n=295 -- an estimate regressing as noise averages out, not an effect
firming up. I called that number encouraging yesterday; on 88 more rows it is
fading, and it should not keep being quoted at its best value.

INTERACTIONS, each scored by partial correlation against the counter residual
controlling for both of its own components: none pass. Only barrel x power
archetype has an incremental exceeding its parts (-0.101 against 0.019) at
n=260 -- the shape Discipline 2 predicts, but a lead, not a finding.

A methodological catch worth keeping. The archetype conditioner was first
built as barrel_pct over league barrel -- a monotone transform of one of its
own components -- so the "interaction" was barrel squared, measuring
nonlinearity in barrel rate rather than any archetype effect, and it produced
this run's only positive result. A Gauss-Jordan pivot test does not catch that,
because the two columns differ by a scale factor. Fixed with a scale-free
collinearity check plus real archetype labels joined from model_snapshots.
Without it this document would have reported a fabricated interaction as the
session's finding.

COMBINED vs COUNTER on total bases: 0.2718 against 0.2647, delta +0.0071, CI
[-0.065, +0.079] -- inconclusive, and the first time a challenger has not
lost. The same engine on hits was -0.116 with a CI excluding zero. That
contrast is the whole argument for total bases, and it is what the physics
said: contact quality governs extra bases, not whether a grounder finds a hole.

Also built: the compound TB projection. skillProjection no longer refuses
total bases -- a deterministic bases-per-hit multiplier had made P(TB>=2)
exactly P(hits>=1), a relabelled hits curve. It is now a convolution over
per-PA base outcomes with hit-type shares shifted by skill. Non-degeneracy is
locked by test.

4,204 tests green (334 suites); web build exit 0.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W1sivYNqY2TS5ftykmHBU9
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# TOTAL BASES — solo baseline, interactions, and the validity blocker
**2026-08-03.** Challenger-only. Counter byte-identical (zero diff on
`probabilityEstimator.js` / `analyzeViaEngine1.js`).
> **HEADLINE 1 — nothing can be gate-validated today, and the reason is my own
> fix.** `statcast_aggregates` is upserted in place and keeps **one as-of date**.
> The first skill backtest was honest only by accident: the nightly refresh was
> unreachable code, so profiles sat frozen at 2026-07-21 — *before* the settled
> window. Repairing that cron (correct for production) refreshed them to today
> and destroyed every prior version. **Point-in-time validation is now
> structurally impossible from that table**, so every number below is
> **contaminated / directional** and none is a gate verdict.
>
> **HEADLINE 2 — on total bases the skill model is at PARITY with the counter**
> (0.2718 vs 0.2647, CI includes zero). On hits it lost by 0.116 with a CI
> excluding zero. Same engine, same day. **The stat choice was the whole story.**
---
## 0. Premise correction
The order states "barrel rate PASSED, exit velo/launch/matchup FAILED solo."
**Nothing passed.** Yesterday's run refused *every* TB feature on
`insufficient_data` (n=295 < 500); barrel rate's marginal r was 0.088 and the
strongest was hard-hit at 0.153. Today at n=383, **hard-hit has fallen to
0.135** — see §3, because that drift is itself the most informative number here.
## 1. The validity blocker, and the fix
```
select updated_at::date, count(*) from statcast_aggregates group by 1;
→ 2026-08-03 | 1387 ← ONE row. No history. 2026-07-21 is gone.
```
A season aggregate dated 2026-08-03 used to score a 2026-07-25 game **contains
that game**. That is leakage, and it is not repairable after the fact.
**Fixed forward:** `statcast_history` (migration applied) retains a dated
snapshot on every refresh, keyed `(as_of_date, sport, season, source_id, role)`.
Point-in-time becomes `where as_of_date < game_date order by as_of_date desc
limit 1` — the profile as it stood *before* the game, by construction. Retention
is best-effort and **cannot fail the refresh**; both properties are unit-tested.
It has one day of data, which is not yet a window.
## 2. Feature → conditioning variable → mechanism (STEP 2)
| interaction | conditioning on | mechanism |
|---|---|---|
| `launch × exit_velo` | each other | Extra bases need **both**: hit hard AND in the air. A 105-mph ground ball is an out; a 25° popup is an out. Neither predicts alone — which is exactly why each can fail solo and the product might not. |
| `exit_velo × pitcher_hard_hit_allowed` | pitcher suppression | A hitter only realises contact quality against a pitcher who permits it. Elite suppression attenuates a power bat; a contact-permitting arm amplifies it. Conditional by construction. |
| `barrel × power archetype` | **real archetype label** | Barrels convert to extra bases for hitters whose lane is power. This is Discipline 2 as a testable claim. |
| `batter_K × pitcher_K` | each other | Strikeout risk compounds (log5 is this shape). A PA lost to a strikeout is a base opportunity that never happens — suppression through **opportunity**, not contact. |
| `pull_rate × park` | park | **UNTESTABLE** — park is passed as 1.0 everywhere and pull rate is not ingested. |
## 3. STEP 1 — solo baseline (the control)
n=383, Bonferroni across 12 tests → corrected α = **0.00417**.
The decider is correlation with the **counter's residual** (`won − p_win`) — a
feature correlating with the raw outcome may simply know what the counter
already knows.
| feature | r vs outcome | **r vs residual** | p | would it pass at n≥500? |
|---|---|---|---|---|
| **batter_hard_hit_pct** | 0.172 | **0.135** | 0.0080 | **No** — |r| < 0.15 *and* p > 0.00417 |
| batter_exit_velo | 0.120 | 0.070 | 0.173 | No |
| batter_barrel_pct | 0.109 | 0.078 | 0.127 | No |
| pitcher_k_pct | −0.094 | −0.087 | 0.093 | No |
| batter_launch_angle | 0.032 | 0.003 | 0.948 | No |
| batter_bb_pct | −0.019 | −0.026 | 0.607 | No |
| pitcher_hard_hit_allowed | 0.024 | 0.035 | 0.501 | No |
| batter_k_pct | −0.009 | −0.003 | 0.952 | No |
**No feature passes solo, and hard-hit is drifting the wrong way.** Its marginal
r went **0.153 (n=295) → 0.135 (n=383)** as sample grew. That is the signature of
an estimate regressing toward its true value as noise averages out, not of a real
effect firming up. Yesterday I called it "the most encouraging number this work
has produced"; on 88 more rows it is fading. **Worth stating plainly, because the
temptation is to keep quoting the older, better number.**
## 4. STEP 3 — interactions, each against its own parts
Incremental signal = partial correlation of the interaction with the residual,
**controlling for both components**. If an interaction is barrel rate in a hat,
regressing out barrel rate collapses it.
| interaction | n | raw r | best component r | **incremental r** | verdict |
|---|---|---|---|---|---|
| `barrel × power archetype` | 260 | −0.046 | 0.019 | **−0.101** | UNDERPOWERED — n below gate |
| `launch × exit_velo` | 383 | 0.007 | 0.070 | −0.053 | UNDERPOWERED |
| `batter_K × pitcher_K` | 378 | −0.050 | 0.087 | −0.024 | UNDERPOWERED |
| `exit_velo × pitcher_suppression` | 378 | 0.048 | 0.073 | 0.013 | UNDERPOWERED |
Only the archetype interaction has an incremental exceeding its parts (0.101 vs
0.019) — the shape Discipline 2 predicts — but at n=260, with a negative sign,
and nowhere near the gate. **It is a lead, not a finding.**
### A methodological catch worth recording
The archetype conditioning variable was first built as
`barrel_pct / LEAGUE.barrel_pct` — a monotone transform of one of its own
components. That interaction was therefore **barrel², measuring nonlinearity in
barrel rate, not an archetype effect at all**, and it produced the run's only
"interaction adds" result (−0.132). Two fixes: a scale-free collinearity check on
the control columns (the Gauss-Jordan pivot test missed it, because the columns
differ by a *scale factor*), and real archetype labels joined from
`model_snapshots` (260 labelled rows: 140 BOMBER, 120 other) so the conditioning
variable is categorical and independent of barrel by construction.
**Without that catch this document would have reported a fabricated interaction
as the session's finding.**
## 5. STEP 4 — combined skill model vs the counter
The compound TB projection was built for this (see §6). Paired bootstrap is
valid at this n even though the *gate* is not.
```
n 383 · pitcher coverage 100% · base rate 0.483
resolution skill TB 0.2718 counter 0.2647
brier skill TB 0.2439 counter 0.2426
delta +0.0071 CI95 [−0.0648, +0.0789] → INCONCLUSIVE
```
**Not a win — but the first time a challenger has not LOST.** For contrast, the
same engine on hits: −0.1161, CI [−0.1892, −0.0426], excluding zero. The
difference between those two lines is the entire argument for moving to total
bases, and it is what the physics said: contact quality governs extra bases, not
whether a grounder finds a hole.
## 6. Built this session: the compound TB projection
`skillProjection` no longer refuses total bases. A deterministic bases-per-hit
multiplier made `P(TB≥2)` **exactly** `P(hits≥1)` — a relabelled hits curve — so
it was refused. It is now a real convolution: each PA yields 0/1/2/3/4 bases with
hit-type shares shifted by skill (barrel → home-run share, exit velo → doubles
and triples), convolved over a PA distribution. A BOMBER gets a 37.5% home-run
share against a slap hitter's 4.5%. Non-degeneracy is locked by test.
## 7. Verdict
- **Solo-proven set for total_bases: EMPTY.** Nothing passes; hard-hit is the
closest and is drifting down.
- **Interaction-proven set: EMPTY.** One lead (archetype × barrel), underpowered.
- **Combined vs counter: INCONCLUSIVE at parity** — genuinely better news than
hits, and still not promotable.
- **Nothing promoted. Counter untouched.**
## 8. Next, in order
1. **Let `statcast_history` accrue.** Nothing here can be validated honestly
until there is a point-in-time window — a week gives a real one. This is now
the binding constraint on the entire programme, and it is a waiting problem,
not a building problem.
2. **Re-run this exact script** once history exists and TB clears n≥500 (383
today, ~117 short). Both arrive on roughly the same timescale.
3. **Archetype × barrel is the one interaction worth carrying forward**, with
real labels and adequate n.
4. **Do not re-run hits.** §5 settles it.
**Not recommended:** quoting the 0.153, lowering n≥500, or promoting on a
parity result. Parity with contamination is not a win.