The Limitations of Quasi-Experimental Studies, and Methods for Data Analysis When a Quasi-Experimental Research Design Is Unavoidable.
Chittaranjan AndradePublished in: Indian journal of psychological medicine (2021)
A quasi-experimental (QE) study is one that compares outcomes between intervention groups where, for reasons related to ethics or feasibility, participants are not randomized to their respective interventions; an example is the historical comparison of pregnancy outcomes in women who did versus did not receive antidepressant medication during pregnancy. QE designs are sometimes used in noninterventional research, as well; an example is the comparison of neuropsychological test performance between first degree relatives of schizophrenia patients and healthy controls. In QE studies, groups may differ systematically in several ways at baseline, itself; when these differences influence the outcome of interest, comparing outcomes between groups using univariable methods can generate misleading results. Multivariable regression is therefore suggested as a better approach to data analysis; because the effects of confounding variables can be adjusted for in multivariable regression, the unique effect of the grouping variable can be better understood. However, although multivariable regression is better than univariable analyses, there are inevitably inadequately measured, unmeasured, and unknown confounds that may limit the validity of the conclusions drawn. Investigators should therefore employ QE designs sparingly, and only if no other option is available to answer an important research question.
Keyphrases
- data analysis
- pregnancy outcomes
- end stage renal disease
- pregnant women
- ejection fraction
- newly diagnosed
- randomized controlled trial
- public health
- bipolar disorder
- double blind
- case control
- open label
- chronic kidney disease
- prognostic factors
- healthcare
- clinical trial
- polycystic ovary syndrome
- type diabetes
- peritoneal dialysis
- emergency department
- phase ii
- patient reported outcomes
- patient reported
- big data
- machine learning
- drug induced
- skeletal muscle
- insulin resistance
- artificial intelligence
- clinical evaluation