# Residual normalization — signal screen

Generated: 2026-10-10T07:53:06.165467+00:00

**Verdict: FAIL**

Previously inspected historical data; no production change or new out-of-sample claim.

| Era | Arm | Windows | Avg stocks | Mean IC | IC 95% interval | Quintile spread |
|---|---|---:|---:|---:|---|---:|
| full | unrestricted_control | 73 | 485.5 | 0.0145 | [-0.0257, 0.0450] | 0.97% |
| full | paired_control | 73 | 485.4 | 0.0145 | [-0.0257, 0.0450] | 0.97% |
| full | normalized | 73 | 485.4 | 0.0128 | [-0.0271, 0.0442] | 0.75% |
| pre_2021 | unrestricted_control | 30 | 472.0 | 0.0078 | [-0.0338, 0.0682] | 0.76% |
| pre_2021 | paired_control | 30 | 471.7 | 0.0078 | [-0.0338, 0.0683] | 0.75% |
| pre_2021 | normalized | 30 | 471.7 | 0.0050 | [-0.0395, 0.0661] | 0.46% |
| post_2021 | unrestricted_control | 42 | 495.2 | 0.0238 | [-0.0125, 0.0630] | 1.26% |
| post_2021 | paired_control | 42 | 495.2 | 0.0238 | [-0.0125, 0.0630] | 1.26% |
| post_2021 | normalized | 42 | 495.2 | 0.0226 | [-0.0147, 0.0631] | 1.06% |

Paired normalized-minus-control IC differences:

- full: -0.0016; 95% interval [-0.004960466538844113, 0.0015584142071432597].
- pre_2021: -0.0028; 95% interval [-0.008151700038659202, 0.001515881215178447].
- post_2021: -0.0012; 95% interval [-0.005965195533675296, 0.003076462018338155].

Screen checks: `{"mean_ic_ge_0_03": false, "at_least_12_windows": true, "pre_2021_positive": true, "post_2021_positive": true}`

Portfolio stage: **not_run_failed_signal_screen**.

Signal IC and quintile spreads are predictive diagnostics, not simulated strategy returns.
Intervals resample paired blocks of four non-overlapping forward windows; they remain exploratory.
The unrestricted control shows the effect of requiring complete formation history.

[Frozen protocol](../docs/research/residual-normalization.md)