TY  - JOUR
T1  - SChool-based health center use and high school dropout rates—reply
AU  - Kerns SU, Pullmann MD, Walker S, Lyon AR, Cosgrove TJ, Bruns EJ
Y1  - 2012/07/01
N1  - 10.1001/archpediatrics.2012.553
JO  - Archives of Pediatrics & Adolescent Medicine
SP  - 675
EP  - 677
VL  - 166
IS  - 7
N2  - 
Treating time-varying variables as fixed can result in a systematic bias referred to as “time-dependent bias,”1 “immortal time bias,”2 or “survival bias.”3 This is a common analytic error; in a review of publications from 9 top medical journals from 1998 to 2002, of 127 studies that used survival analysis with time-dependent variables, 41% (52 studies) were susceptible to time-dependent bias because they did not appropriately operationalize at least 1 time-varying variable in the model.1

SN  - 1072-4710
M3  - doi: 10.1001/archpediatrics.2012.553
UR  - http://dx.doi.org/10.1001/archpediatrics.2012.553
ER  -