Research Information System
Türkiye Klinikleri Biyoistatistik Dergisi, vol.5, no.2, pp.49-54, 2013 (Peer-Reviewed Journal)
Da ta with mis sing va lu e are com mon in cli ni cal stu di es. This study in ves ti -
ga ted to as sess the ef fects of dif fe rent mis sing da ta analy sis tech ni qu es on the per for man ce of Cox
pro por ti o nal ha zard mo del. Ma te ri al and Met hods: In or der to se e how samp le si ze and mis sing ra -
te ef fect the mis sing da ta analy sis tech ni qu es, we de ri ved the sur vi val da ta with 25, 50 and 100
samp le si zes. So me ele ments of the sur vi val da ta with dif fe rent samp le si ze we re de le ted in dif fe -
rent ra tes un der MAR (Mis sing at Ran dom) as sump ti on to ge ne ra te in comp le te da ta sets which had
5%, 10%, 20% and 40% mis sing va lu e for each da ta. Da ta sets with mis sing va lu es we re comp le ted
by fi ve mis sing da ta analy sis tech ni qu es (comp le te ca se Analy sis-CCA, me an im pu ta ti on, reg res si -
on im pu ta ti on-REG, ex pec ta ti on ma xi mi za ti on-EM al go rithm, mul tip le im pu ta ti on-MI). The new
comp le ted da ta sets we re analy zed by Cox pro por ti o nal ha zard mo del and the ir re sults we re compa
red with re sults of ori gi nal da ta. Re sults: The dif fe ren ce bet we en the tech ni qu es grew for in cre -
a sing mis sing ra te and whi le the samp le si ze in cre a sed the met hods we re si mi lar to each ot her. CCA
was the most af fec ted from samp le si ze. The es ti ma tes from the met hods REG, EM and MI we re very
si mi lar to each ot her and re al va lu e. Conc lu si on: Mul tip le im pu ta ti on met hod as im pu te mo re than
one va lu e for each mis sing va lu e sho uld be pre fer red ins te ad of sing le im pu ta ti on met hods as impu
te only one va lu e for each mis sing va lu e.