Psychopharmacology bulletin

Overall JE, Atlas RS.
PMID: 8290658
Psychopharmacol Bull. 1993;29(2):141-7.

Motivations for undertaking interim analyses differ, as do the methods proposed by different authors. This article evaluates five interim analysis procedures with regard to different requirements. The five procedures differ with respect to concern for the presence or absence...

Psychopharmacology bulletin

Overall JE, Shobaki G, Shivakumar C, Steele J.
PMID: 9564195
Psychopharmacol Bull. 1998;34(1):25-33.

Statistical models for calculating sample sizes for controlled clinical trials often fail to take into account the negative impact that dropouts have on the power of intent-to-treat analyses. Empirically defined dropout correction coefficients are proposed to adjust sample sizes...