The intervention selection bias: an underrecognized confound in intervention research.
Selection bias can be the most important threat to internal validity in intervention research, but is often insufficiently recognized and controlled. The bias is illustrated in research on parental interventions (punishment, homework assistance); medical interventions (hospitalization); and psychological interventions for suicide risk, sex offending, and juvenile delinquency. The intervention selection bias is most adequately controlled in randomized studies or strong quasi-experimental designs, although recent statistical innovations can enhance weaker designs. The most important points are to increase awareness of the intervention selection bias and to systematically evaluate plausible alternative explanations of data before making causal conclusions.
Department of Psychology, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, NE 68198-5450, USA. rlarzelere@unmc.edu
Robert E
RE
Larzelere
Brett R
BR
Kuhn
Byron
B
Johnson
D002648:Child; D005260:Female; D006801:Humans; D007604:Juvenile Delinquency / Q000517:prevention & control*; D008297:Male; D001523:Mental Disorders / Q000517:prevention & control*; D016487:Parenting; D011613:Psychotherapy / Q000379:methods*; D011678:Punishment; D012107:Research Design; D012944:Social Support; D013406:Suicide, Attempted / Q000517:prevention & control*