RT Journal
A1 Zlowodzki, Michael
A1 Bhandari, Mohit
T1 Outcome Measures and Implications for Sample-Size Calculations
JF The Journal of Bone & Joint Surgery
JO The Journal of Bone & Joint Surgery
YR 2009
FD May 1
VO 91
IS Supplement_3
SP 35
OP 40
DO 10.2106/JBJS.H.01602
UL http://dx.doi.org/10.2106/JBJS.H.01602
AB This article focuses on items to consider when selecting outcome measures for a clinical study. The choice of outcome measures depends largely on the research question and the study design. Sample-size requirements can vary greatly, depending on the type and the number of outcome measures selected. In this paper, we review the differences between categorical and continuous outcomes as well as the differences between primary and secondary outcomes and we discuss the concept of minimally important differences and the problems associated with composite outcomes. We also provide instruction on how to conduct and present a sample-size calculation.