What is a group sequential design?

What is a group sequential design?

Group sequential design is an example of a statistical approach in clinical trial design. It means that the sample size of the trial is not fixed in advance, and data is sequentially evaluated as it is collected. This is known as interim analysis, and might be carried out at several points in time.

What occurs in a sequential clinical trial?

What occurs in a sequential clinical trial? Data are continuously analyzed as they become available. The first half of the subjects is assigned to the experimental group and the second half is assigned to the control group. Data are continuously analyzed as they become available.

What is the futility boundary?

A futility boundary (futility stopping boundary, rarely futility limit) is a statistical decision boundary used in sequential testing such as an AGILE A/B test. It is built in such a way that it maintains the type II error probability (beta β) larger than a specified level, on average.

What is a futility analysis?

In technical terms, futility monitoring refers to a statistical procedure for stopping the trial early if it appears that the experimental arm is unlikely to be shown definitively better than the control arm if the trial is continued to the final analysis.

What is group sequential testing?

Group sequential trials are used in clinical trials. A group sequential design is a type of adaptive design where the number of patients isn’t set in advance. Patients are divided into an equal number of groups and data is analyzed at pre-determined points in the trial.

What are sequential methods?

The sequential method is used to allocate the cost of service departments to other departments within an organization. Under this approach, the cost of each service department is allocated one department at a time. Because this method involves a one-way cost allocation, it is not entirely theoretically correct.

What is sequential technique?

Sequential sampling is a non-probability sampling technique wherein the researcher picks a single or a group of subjects in a given time interval, conducts his study, analyzes the results then picks another group of subjects if needed and so on.

What are continuous endpoints?

« Back to Glossary Index. A measurement, often expressed in numbers, collected in a clinical trial that represents a specific variable.

What is Alpha spending?

Alpha-spending is an approach of distributing (spending) the type I error (denoted alpha) over the duration of a sequential A/B test. Alpha-spending makes it possible to perform sequential testing while maintaining the overall error probability of the procedure.

What type of poem is futility?

‘Futility’ takes the form of a short elegy. An elegy, or an elegiac poem, was a form of writing that had its first depiction in the 16th century, but had not been gratuitously used before. Only a handful of famous elegiac poems come to mind, chief of which is Thomas Gray’s Elegy Written in a Country Churchyard.

What does it mean when a study is stopped for futility?

The term ‘futility’ is used to refer to the inability of a clinical trial to achieve its objectives. In particular, stopping a clinical trial when the interim results suggest that it is unlikely to achieve statistical significance can save resources that could be used on more promising research.

When to stop a trial in group sequential design?

In contrast, group sequential designs allow an early stopping of the trial at interim, either for efficacy when the treatment effect is significant or for futility when the treatment effect seems too small to justify a continuation of the trial.

How to choose futility boundaries for group sequential designs?

The “ Methods ” section introduces first the study design, the test problem and general principles of group sequential designs and then describes the new approach of choosing ‘optimal’ futility stopping boundaries as motivated above.

How to define group sequential boundaries in rpact?

Define the (abstract) group-sequential boundaries of the design using the function getDesignGroupSequential (). Calculate sample size for the endpoint of interest by feeding the abstract boundaries from step 1. into specific functions for the endpoint of interest.

When to use one-sided tests in group sequential design?

If futility boundaries are specified, however, only one-sided tests are permitted. For simplicity, it is often preferred to use one-sided tests for group-sequential designs (typically, with \\ (\\alpha = 0.025\\) ).