Interim analysis: The alpha spending function approach
Article first published online: 15 OCT 2006
Copyright © 1994 John Wiley & Sons, Ltd.
Statistics in Medicine
Volume 13, Issue 13-14, pages 1341–1352, 15 - 30 July 1994
How to Cite
Demets, D. L. and Lan, K. K. G. (1994), Interim analysis: The alpha spending function approach. Statist. Med., 13: 1341–1352. doi: 10.1002/sim.4780131308
- Issue published online: 15 OCT 2006
- Article first published online: 15 OCT 2006
Interim analysis of accumulating data in a clinical trial is now an established practice for ethical and scientific reasons. Repeatedly testing interim data can inflate false positive error rates if not handled appropriately. Group sequential methods are a commonly used frequentist approach to control this error rate. Motivated by experience of clinical trials, the alpha spending function is one way to implement group sequential boundaries that control the type I error rate while allowing flexibility in how many interim analyses are to be conducted and at what times. In this paper, we review the alpha spending function approach, and detail its applicability to a variety of commonly used statistical procedures, including survival and longitudinal methods.