Group sequential designs

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Group sequential designs New

Why wait until you finish collecting data to analyze the results of your clinical trial? Group sequential designs (GSDs) allow you to preplan interim analyses of clinical-trial data while controlling the familywise error rate. If interim results are conclusive, you can stop the trial early for efficacy or futility, saving resources and sparing participants from receiving inferior treatments. Use Stata's gsdesign commands or interactive Control Panel to calculate efficacy- and futility-stopping boundaries, compute sample sizes for interim analyses, compare GSDs with equivalently powered fixed studies, and graph the stopping boundaries for your trial.

Learn about Group sequential designs.

Watch Group sequential designs.

GSD methods

One-sample mean test
Two-sample means test
One-sample proportion test
Two-sample proportions test
Log-rank test of survivor functions
User-defined test

Stopping boundaries

Classical O'Brien–Fleming bounds
Classical Pocock bounds
Classical Wang–Tsiatis bounds
Error-spending O'Brien–Fleming-style bounds
Error-spending Pocock-style bounds
Error-spending Kim–DeMets bounds
Error-spending Hwang–Shih–de Cani bounds

Stopping for

Efficacy
Futility
Both efficacy and futility

Futility boundaries

Binding
Nonbinding

Control Panel interface

Select analysis type from descriptive summaries
Specify analysis interactively
Automated tables and graphs
Customizable tables and graphs
Command interface

Graph boundaries

Show critical values at each look
Compare with fixed-study critical values
Customizable

Interim analyses

Evenly spaced
Unevenly spaced at user-specified increments

Additional resources

Adaptive Designs: Group Sequential Trials Reference Manual

Also see power and sample-size analysis for fixed-sample designs.

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