Attrition in a longitudinal study with hard-to-reach participants was reduced by ongoing contact

David, Michael C., Alati, Rosa, Ware, Robert S. and Kinner, Stuart A. (2013) Attrition in a longitudinal study with hard-to-reach participants was reduced by ongoing contact. Journal of Clinical Epidemiology, 66 5: 575-581. doi:10.1016/j.jclinepi.2012.12.002

Author David, Michael C.
Alati, Rosa
Ware, Robert S.
Kinner, Stuart A.
Title Attrition in a longitudinal study with hard-to-reach participants was reduced by ongoing contact
Journal name Journal of Clinical Epidemiology   Check publisher's open access policy
ISSN 0895-4356
Publication date 2013-05
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.jclinepi.2012.12.002
Volume 66
Issue 5
Start page 575
End page 581
Total pages 7
Place of publication Philadelphia, PA United States
Publisher Elsevier
Collection year 2014
Language eng
Formatted abstract
Objectives: Minimizing attrition is a key objective in longitudinal research, with possible consequences being additional bias and reduced generalizability. Identifying determinants of attrition is essential in determining attrition prevention strategies. The objective of this study was to investigate a number of these determinants, with an emphasis on contactability.

Study Design and Setting:
Data were taken from the Passports project, a randomized controlled trial of an intervention to provide postrelease support to ex-prisoners in Queensland, Australia. Measures of contactability included intervention intensity, baseline collaterals, and follow-up telephone calls, with attrition at follow-up being the outcome event. Multivariable modeling was used to assess the independent effects of these measures on attrition.

Attrition was found to be more likely among those who were not contacted between the release and follow-up (adjusted odds ratio [AOR]: 2.93; 95% confidence interval [CI]: 1.87, 4.60), did not provide collaterals (AOR: 2.58; 95% CI: 1.68, 3.97), and received more than four telephone calls (AOR: 2.42; 95% CI: 1.61, 3.63). Evidence of dose-response relationships between attrition and the measures of collaterals and telephone calls was also seen to exist.

These findings have implications for sample size maintenance, especially those involving hard-to-reach populations. Subject to cost constraints and possible diminishing returns, researchers should endeavor to implement a study protocol that facilitates continued contact during follow-up.
Keyword Attrition
Hard to reach
Repeated contacts
Sample size
Collateral contacts
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Public Health Publications
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