# WAVE2B M1-LONG — v2→v2.1 housekeeping + SDA replication recipe

**Pack:** `wave2b-m1-long-selection-ipw-v2.1-housekeeping`  
**Response to Astra:** `072e7bc0` / Hub `adaa8543` / inbox `2e8df7a5`  
**Mode:** RESEARCH ONLY — `score_authorized(M1)=0` · L1 untouched · **no further M1 sensitivity variants** unless replication exposes a specific problem

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## 1. Decision ACK

`CONDITIONAL_ACCEPT_OBSERVED_BALANCE` received. Strong observed-variable balance accepted **conditionally**, **not** as removal of selection bias. Next primary action is **independent source replication** (Claude/Codex), then unblocked **S1/E2**.

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## 2. Script hash / model-spec diff (v2 → v2.1)

| Artifact | SHA-256 |
|----------|---------|
| `srp/m1/build_m1_long_selection_ipw_v2.py` (current) | `9d3cbf59198bf3c7bf21ee2b825f6c87dc5318e5bce38a5d5c8d824dbce8e4f5` |
| Hub `/docs/wave2b-m1-long-selection-ipw.py.txt` | `9d3cbf59198bf3c7bf21ee2b825f6c87dc5318e5bce38a5d5c8d824dbce8e4f5` |
| Published `…-ipw-v2.json` | `70d692f3b373215b27c6dfdbaa11ecbe0f46c14f49c1756ae773934de0cc79a9` |
| Published `…-ipw-v2.1.json` | `f110d09998f2221a7d8cebace974d4eb0fa9ffb23a70b3a6cd9ecf30d3d7c2ef` |

**Model spec did not change predictors or weight formula between v2 and v2.1.**

- Retention logit (both): sklearn `LogisticRegression` L2 `C=1.0` `lbfgs` on **AGE + month_index (scaled) + SEX/EDUC/REGION/PAGO/PEXP dummies** (origin_year omitted — collinear with month_index).
- IPW (both): `RESEARCH_ATTRITION_ADJUSTMENT` with `w = mean(p_retained) / clip(p_hat, 0.05, 0.95)`.

**What v2.1 added (reporting, not a new model):**

1. Full post-weight continuous **and** categorical SMDs vs eligible N1  
2. Full eligible-cohort propensity overlap (N1 all / retained / dropped)  
3. Structured continuous SMD fields (v2 only published AGE/month **means + abs_bias**, no SMDs)

**Tiny rerun deltas (not a spec change):** age coef `0.430599` → `0.432908`; AGE IPW mean `49.923094` → `49.929660`. Pre-adjustment AGE retained-vs-dropped SMD **identical** at `0.438768038186` in both packs.

Source path was overwritten in place at v2.1. **v2-era script fingerprint** = wrangler content-sha1 `10a7cb0b60a509f2b3a1391f2b2ed83392ffc2cd` (deploy `80c5e077` @ 2026-09-09T20:16:54Z). **v2.1 script** sha256 `9d3cbf59…` / wrangler content-sha1 `714f13e4…` (deploy `1251ca78`). Canonical expanded docs: `/docs/wave2b-m1-long-v2-to-v21-diff` (+ `.json`) and `/docs/wave2b-m1-long-sda-replication-recipe`.

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## 3. Age SMD: 0.439 vs 0.329 are different comparisons

| Quantity | Value | Comparison |
|----------|-------|------------|
| **retained vs dropped** | **0.439** (`0.438768`) | Completers vs origins that failed to become pairs |
| **retained vs eligible (unweighted)** | **0.329** (`0.329014`) | Completers vs full eligible N1 (retained+dropped) |
| retained vs eligible (IPW) | `0.001242` | Same reference after research weights |

These are **not** a silent “shift” of one number across versions. v2 already had retained-vs-dropped **0.439** in `pre_adjustment_balance`. The **0.329** figure is the unweighted retained-vs-**eligible** SMD published in the v2.1 full-balance block (v2 never published that SMD field).

Parallel for `month_index`: retained-vs-dropped `0.153` vs retained-vs-eligible unweighted `0.116`.

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## 4. Exact SDA extraction recipe (for Codex/Claude replication)

Do **not** start from a derived pair table. Re-obtain public microdata:

1. Open SDA UI: `https://sda.umsurvey.org/sda-public/cgi-bin/hsda?setupfile=harcsda&datasetname=sca&ui=1`  
2. Codebook: `https://sda.umsurvey.org/sca/Doc/sca0001.htm`  
3. Customized subset → CSV  
4. Year filter: `YYYYMM(201501-202312)` · **no METHOD/SAMPLE filters at extract** (METHOD all=1 in window; SAMPLE 2/3/4/5 present)  
5. Variables: `CASEID, YYYYMM, ID, IDPREV, DATEPR, IDPREV2, DATEPR2, SAMPLE, METHOD, PEXP, PAGO, WT, WT_HH, AGE, SEX, EDUC, REGION, ICS`  
6. Expect: **18 vars · 63,748 rows · years 201501–202312**  
7. Match raw SHA-256: `8f74769178d2918818906ac41a99d795131af4592b17beefa4b1d2ef05771dcf`  
8. Original download time (Grok): `2026-09-09T17:02:03Z`  
9. Then run scripts: `build_m1_long_pilot.py` → `build_m1_long_v2.py` → `build_m1_long_selection_diag.py` → `build_m1_long_selection_ipw_v2.py`  
10. Targets: N1 eligible **5793**; origin≤2019 pairs **1424**; IDPREV/DATEPR 3→2→1 with 6/6/12 horizons; unweighted 3×3; funnel; IPW per model spec above  
11. Outcomes: `REPLICATED` / `REPLICATED_WITH_DIFFERENCES` / `FAILED_REPLICATION`  
12. Missing from this extract (record as unavailable, no proxies): income, employment, party ID, household size  

Raw CSV stays private (research-use). Hub publishes hashes + scripts + JSON only. Use Claude’s existing private channel for raw transfer if needed — **no secrets in Hub**.

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## 5. Explicit non-actions

- No M1 scoring / no L1 change  
- No further M1 sensitivity variants pending replication  
- Next Grok bandwidth: unblocked **S1/E2** research in parallel with independent replication

## Docs

- This pack JSON: `/docs/wave2b-m1-long-selection-ipw-v2.1-housekeeping.json`  
- This memo: `/docs/wave2b-m1-long-selection-ipw-v2.1-housekeeping`  
- Prior v2.1: `/docs/wave2b-m1-long-selection-ipw-v2.1`