Open AccessEvaluating Public Health Interventions: 3. The Two-Stage Design for Confounding Bias Reduction—Having Your Cake and Eating It Two
Author(s) -
Donna Spiegelman,
Claudia Rivera-Rodriguez,
Sebastien Haneuse
Publication year - 2016
Publication title -
american journal of public health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.284
H-Index - 264
eISSN - 1541-0048
pISSN - 0090-0036
DOI - 10.2105/ajph.2016.303250
Subject(s) - confounding , psychological intervention , environmental health , information bias , public health , medicine , tanzania , intervention (counseling) , selection bias , psychiatry , geography , nursing , pathology , environmental planning
In public health evaluations, confounding bias in the estimate of the intervention effect will typically threaten the validity of the findings. It is a common misperception that the only way to avoid this bias is to measure detailed, high-quality data on potential confounders for every intervention participant, but this strategy for adjusting for confounding bias is often infeasible. Rather than ignoring confounding altogether, the two-phase design and analysis-in which detailed high-quality confounding data are obtained among a small subsample-can be considered. We describe the two-stage design and analysis approach, and illustrate its use in the evaluation of an intervention conducted in Dar es Salaam, Tanzania, of an enhanced community health worker program to improve antenatal care uptake.