RT Journal Article
SR Electronic
T1 Sample sizes based on three popular indices of risks
JF General Psychiatry
JO Gen Psych
FD BMJ Publishing Group Ltd
SP e100011
DO 10.1136/gpsych-2018-100011
VO 31
IS 3
A1 Hongyue Wang
A1 Bokai Wang
A1 Xin M Tu
A1 Jinyuan Liu
A1 Changyong Feng
YR 2018
UL http://gpsych.bmj.com/content/31/3/e100011.abstract
AB Sample size justification is a very crucial part in the design of clinical trials. In this paper, the authors derive a new formula to calculate the sample size for a binary outcome given one of the three popular indices of risk difference. The sample size based on the absolute difference is the fundamental one, which can be easily used to derive sample size given the risk ratio or OR.