Strengths and Weaknesses

A well-developed RCT provides the most secure basis for determining causal inferences about the effects of a treatment

Considered to be the most rigorous quantitative research design

Can eliminate confounding variables by identifying and randomizing them into the control group

Blinding can function to separate the true effects of the intervention from the participants’ and investigators’ expectations (placebo effect) and knowledge of the intervention

Blinding can reduce bias

Findings may be generalizable with a sufficiently large sample size (power calculation)

Expensive (ex. a large trial may require more investigators, if a drug trial developing a placebo and packaging to mirror that of the intervention)

Time-consuming (not good when the program is emergent or must be completed rapidly)

Blinding can cause challenges in recruitment and retention of study participants (ex. may drop out if they feel they were randomized to placebo)

Often difficult to obtain true double blinding (ex. side effects obvious in the treatment arm, participants discussing on social media and online groups (ex. “Patientslikeme”), placebo can be difficult to make identical in look and packaging to intervention)

Cannot be performed retrospectively, must be fully developed from the beginning

Needs a larger sample size, smaller sample sizes may not cause exaggerated treatment effects, poor generalizability

Cannot be used as exploratory research, initial research and formative testing must be performed prior and functions to inform the study design

Not effective when the treatment outcome is difficult to measure