Topic: Unblinded Re-Estimation and the Promising Zone

Discrete Sample Sizes and Rounding

Deterministic Conditional-Power Re-Estimation Rules

Deriving Sample Size From a Conditional-Power Target

Defining the Promising Zone

Deriving Conditional Power in the Normal Model

Deriving Expected Sample Size Under Re-Estimation

Conditional Power Under a Prespecified Effect

Conditional Power Under Alternative Variance Assumptions

Conditional Power Curves Across Interim Results

Conditional-Power Rules Versus Effect-Threshold Rules