Can research assessments themselves cause bias in behaviour change trials? A systematic review of evidence from solomon 4-group studies.

ABSTRACT:

Background

The possible effects of research assessments on participant behaviour have attracted research interest, especially in studies with behavioural interventions and/or outcomes. Assessments may introduce bias in randomised controlled trials by altering receptivity to intervention in experimental groups and differentially impacting on the behaviour of control groups. In a Solomon 4-group design, participants are randomly allocated to one of four arms: (1) assessed experimental group; (2) unassessed experimental group (3) assessed control group; or (4) unassessed control group. This design provides a test of the internal validity of effect sizes obtained in conventional two-group trials by controlling for the effects of baseline assessment, and assessing interactions between t

SUBMITTER: McCambridge J 

PROVIDER: S-EPMC3198466 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature