Module Components

• Learning Activities

Topics

• Critical Appraisal Principles
• Systematic Review Appraisal
• Randomized Control Trial Appraisal
• Cohort Study Appraisal
• Case Control Study
• Module 8 Self-Review

NRSG 790-Methods for Research and Evidence-Based Practice

Module 8: Critically Appraising Quantitative Evidence

Randomized Control Trial Appraisal

An RCT is a type of interventional or experimental study design. Participants (individuals or groups) are randomly allocated to receive either the new intervention being tested or a control treatment (usually the standard treatment or a placebo). Each arm of the study is then followed up and the amount or severity of the disease measured in the intervention group and compared with the control group. RCTs are by definition prospective.

Advantages

• Good randomization will “wash out” any population bias
• Easier to blind/mask than observational studies
• Results can be analyzed with well known statistical tools
• Populations of participating individuals are clearly identified

Disadvantages

• Expensive in terms of time and money
• Volunteer biases: the population that participates may not be representative of the whole
• Does not reveal causation
• Loss to follow-up attributed to treatment

Example

• Ensrud, K. E., Stock, J. L., Barrett-Connor, E., Grady, D., Mosca, L., Khaw, K., et al. (2008). Effects of raloxifene on fracture risk in postmenopausal women: The raloxifene use for the heart trial. Journal of Bone and Mineral Research, 23(1), 112-120.

This research studied the effect of raloxifene on fracture risk in postmenopausal women, and found that the women who took raloxifene over the same five year period of time as the women who did not reduced their risk of clinical vertebrate fracture.

Randomized Control Trial Critical Appraisal Tool - See "Tool" in Lesson Plan under "Recommended Reading"