Context Function Audit

This report reviews the response functions already fitted by Forward Portable-Matchup Contextual RAPM. It does not train a candidate model or claim that a visible curve is a causal basketball relationship.

For season \(s\), feature \(k\), and relative feature difference \(z\), the audited total component is:

This is the model's original orientation-symmetrized total contextual response, before the season-specific reference field turns it into portable composition and matchup-residual terms. It is therefore the appropriate object for choosing a future function family.

Review Protocol

Inspect the fitted response only inside its observed central support. A function family is a candidate for a future refit only when its response is smooth and stable across seasons and its shape has a defensible interpretation. Engineered interactions face a higher bar: a visually irregular interaction is not retained merely because it appeared in an earlier feature set.

The next modeling decision is deliberately editorial and prospective:

• retain a linear term when the atlas is stable and approximately straight;
• consider a low-complexity spline only for stable nonlinear responses;
• consider a monotone constrained response only with a defensible direction;
• re-linearize or remove unstable interactions before paying for a full refit.

Current Audit

Source artifact: forward-portable-matchup-contextual-rapm-2025-26-20260808T165815Z-0d9d87f0. The audit evaluates 29 saved seasonal states without refitting. Faint curves are individual seasons, orange is the historical median, and green is 2025-26.

The x-axis is each season's 5th-to-95th percentile of possession-weighted independent reference-unit differences. This makes curve shapes comparable across eras without treating raw feature scales as stationary.

Temporal Direction Versus Scatter

Each point below is a season's signed central response contrast: the 95th-percentile response minus the 5th-percentile response. Orange is a least-squares time trend. A low R² means the annual movement is primarily scatter rather than a sustained directional evolution.

Stability Summary

Median range is the within-season 5th-to-95th response range. Median curvature is the largest departure from that season's endpoint chord. Median turns counts direction reversals across the central response interval. Cross-season SD is the median seasonal standard deviation at matched percentiles. These are screening diagnostics, not automatic feature-selection rules.

Immutable generated artifact: artifacts/analysis/context_function_audit/2025-26/context-function-audit-2025-26-15Z-0d9d87f0.