Premium
PRACTICAL p ‐VALUE ADJUSTMENT FOR OPTIMALLY SELECTED CUTPOINTS
Author(s) -
HILSENBECK SUSAN GALLOWAY,
CLARK GARY M.
Publication year - 1996
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/(sici)1097-0258(19960115)15:1<103::aid-sim156>3.0.co;2-y
Subject(s) - bonferroni correction , statistics , permutation (music) , econometrics , value (mathematics) , mathematics , medicine , acoustics , physics
This paper concerns a series of simulations undertaken to examine the effects of two data features – number of cutpoints and true marker prognostic effect size – on three methods of p ‐value adjustment (asymptotic, P acor ; improved Bonferroni, P bon ; and empirical permutation, P emp ). H 0 rejection rates for P emp and P bon are almost indistinguishable from those for an independent validation sample ( P vld ), while those of P acor are somewhat conservative, especially when the number of cutpoints is small. Analysis of a new breast cancer prognostic marker, heat shock protein 70, illustrates the methods. These results underscore many of the problems associated with data‐derived cutpoints in general, and the need for p ‐value adjustment.