Attrition and generalizability in longitudinal studies: findings from a 15-year population-based study and a Monte Carlo simulation study
By Kristin Gustavson, T. von Soest, E. Karevold, E. Røysamb. BMC Public Health, 2012
659 citations recorded by the source corpus.
BackgroundAttrition is one of the major methodological problems in longitudinal studies. It can deteriorate generalizability of findings if participants who stay in a study differ from those who drop out. The aim of this study was to examine the degree to which attrition leads to biased estimates of means of variables and associations between them.MethodsMothers of 18-month-old children were enrolled in a population-based study in 1993 (N=913) that aimed to examine development in children and their families in the general population. Fifteen years later, 56% of the sample had dropped out. The present study examined predictors of attrition as well as baseline associations between variables among those who stayed and those who dropped out of that study. A Monte Carlo simulation study was also performed.ResultsThose who had dropped out of the study over 15 years had lower educational level at baseline than those who stayed, but they did not differ regarding baseline psychological and relationship variables. Baseline correlations were the same among those who stayed and those who later dropped out. The simulation study showed that estimates of means became biased even at low attrition rates and only weak dependency between attrition and follow-up variables. Estimates of associations between variables became biased only when attrition was dependent on both baseline and follow-up variables. Attrition rate did not affect estimates of associations between variables.ConclusionsLong-term longitudinal studies are valuable for studying associations between risk/protective factors and health outcomes even considering substantial attrition rates.
Subfields: Health, Management Science and Operations Research, Statistics and Probability
View Paper: https://www.semanticscholar.org/paper/2ff258a4566f80197ec4b60047c2a5948440005e
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Citations in the corpus
- Behavioural Brain Research (2016, neutral): “Thereafter, the training of the two Cohorts was matched”
- Systems Perspective of Amazon Mechanical Turk for Organizational Research: Review and Recommendations (2017, background): “Critically, the 47% retention rate compared to nationally representative annual surveys is low (around 90%; Gustavson et al., 2012; Schoeni et al., 2013), although large scale epidemiological surveys have completion (attrition) rates that fall within the 30 to 70% range.”