Cooldown, Seasonality, and Anticipation

Cooldown excludes observed periods between launch and measurement. It is useful when response builds gradually, attribution matures, or short-term launch noise is outside the estimand. It also removes data and can reduce power.

GeoSC counts observed periods. With daily data, cooldown_periods: 7 excludes seven observed days; missing dates make that different from seven calendar days. The resolved analysis window is persisted in validation and result artefacts.

Cooldown does not fix anticipation. If customers or media respond before the declared launch, the pre-period is contaminated. Move the intervention boundary only when the behavioural timing supports it, not to improve fit.

Power’s native CLI does not apply the inference cooldown resolver. Set the power split and simulated duration to represent the actual measurement design, and document the translation.

Historical data should cover comparable seasonal conditions. The factor VAR(1) DGP has no explicit day-of-week, holiday, or campaign-season terms. A long but non-comparable history can be worse than a shorter seasonally relevant window; use pre-specified sensitivity checks.