Anne Young|Jennifer Powers|Sandra Bell
Attrition in longitudinal studies: who do you lose?
University of Newcastle Australia|University of Newcastle Australia|University of Newcastle Australia
describe risk factors various types attrition three age cohorts women longitudinal study discuss strategies minimise attritionanalysis survey data australian longitudinal study womens health collected mailed questionnaire 1996 study recruited surveyed national random sample younger 1823 years n 14247 midage 4550 years n 13716 older women 7075 years n 12432 began staggered cycle mailed followup questionnaires 1998 midage 1999 older 2000 younger demographic health social risk factors attrition examined using multivariate analysisattrition survey 2 highest among younger women 32 mainly participants contactable 21 lower among older 16 midage women 10 survey 1 survey 2 nonrespondents likely report less education born nonenglishspeaking country current smoker cohorts poorer health midage older cohort difficulty managing income younger midagealthough magnitude different types attrition found differ age several risk factors attrition remained consistent findings important inform future studies ways lessen prevent systematic loss participantsrecruitment followup methods longitudinal studies tailored maximise retention participants higher risk dropout