BioStatHub Knowledge Center

Educational articles about Simon's two-stage design, power functions, phase II trial design selection, sample size, early stopping, and BioStatHub workflows.

The Simon two-stage design calculator generates and compares the designs these articles explain. About BioStatHub describes who develops it and how it is validated.

Articles

Fundamentals

20 min read | Beginner

Simon's Two-Stage Design: A Guide to Phase II Clinical Trials

Explains how Simon's two-stage design works in single-arm Phase II trials: the parameters and decision rules, Type I error and power, probability of early termination, expected sample size, a worked example, and how optimal, minimax, and admissible designs compare.

8 min read | Beginner

How to Choose p₀ and p₁ in a Simon's Two-Stage Design

A practical guide to selecting p₀ and p₁ for Simon's two-stage designs, including the effect size concept, the four-way trade-off with α and β, and an iterative workflow for finding a feasible design.

5 min read | Beginner

How to Choose α and β in a Simon's Two-Stage Design

A practical guide to choosing α and β in a Simon's two-stage design, including their clinical interpretation, effect on sample size, common choices, and how to justify them in a Phase II protocol.

9 min read | Beginner

Why Phase II Clinical Trials Need Early Stopping

Explains why Phase II trials use prospective futility rules, how Simon’s two-stage design balances patient protection with statistical power, and how PET and ESS make the benefit visible.

Design Selection

9 min read | Intermediate

Optimal vs. Minimax Simon Designs: Which Should You Choose?

A practical guide to choosing between Simon's Optimal and Minimax two-stage designs by comparing expected sample size under p₀, early stopping, maximum enrollment, and the rationale behind each optimization objective.

Sample Size

9 min read | Intermediate

Expected Sample Size in Two-Stage Trials

Explains how expected sample size depends on the response probability, how it relates to probability of early termination, and how it can help compare Simon's two-stage designs.

Tutorials

Operating Characteristics

17 min read | Intermediate

How to Interpret the Operating Characteristics of a Simon's Two-Stage Design

Explains how probability of early termination, probability of reaching stage 2, expected sample size, and the power function describe a Simon's two-stage design as a system, why each is a function of the true response probability rather than a fixed number, and how to read a three-panel operating-characteristics plot.