Using Linkage to Electronic Primary Care Records to Evaluate Recruitment and Nonresponse Bias in The Avon Longitudinal Study of Parents and Children

doi:10.1097/01.ede.0000472624.99897.ff

Abstract

Highlights

To the Editor: Participation is often incomplete in observational research—because of initial failure to recruit or loss to follow-up— resulting in loss of statistical power and possible bias
Selective participation often leads to biased prevalence estimates, but appears to be less important in relation to estimates of exposure–outcome associations, though exceptions have been reported.[1,2,3,4,5,6,7]
Confidence intervals were constructed around the logarithm of the ratios of cumulative incidence and relative odds ratios (RORs) using a nonparametric bootstrap method

Summary

Introduction

To the Editor: Participation is often incomplete in observational research—because of initial failure to recruit or loss to follow-up— resulting in loss of statistical power and possible bias. We used the linked resource to define the cumulative incidence (by ages 11 and 19) of six outcomes: any mental illness, any respiratory illness (excluding asthma), asthma and/or allergies, ever smoked (up to 19 only), been pregnant (19 only), and been classified as “child at risk” (eAppendix; http://links.lww.com/EDE/ A898). We calculated the cumulative incidence among those eligible to take part in ALSPAC, those who had enrolled and those who participated at 10 and 17 years of age.

Results

Conclusion