Frozen model and validation population

Define frozen model and applicability

A frozen model includes coefficients, intercept or baseline survival, preprocessing and input definitions. Independence from development data must be explicit. Plan precision for several performance domains rather than relying on a minimum event count alone.

Flow diagram

Steps

Identify the exact model

Obtain the exact frozen model, preprocessing, coefficients, intercept or baseline survival and required input definitions. Record model version and any unavailable components.

Define independent validation setting

Document geography, time, sites and independence from development.

Compare population and case mix

Record eligibility and differences from the original target population.

Specify validation sample size

Plan precision for calibration, discrimination and key subgroups.

Freeze untouched evaluation plan

Keep model updating separate from the original-model validation.