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M3 Practice Based Learning and Improvement Presentation Guide: Step 5: Validity

This guide is a resource for M3 students and faculty for the Practice Based Learning and Improvement (PBLI) presentation assignment.

Using a RCT - FRISBEE: Validity of Research

F Follow-Up
R Randomization
I Intention-to-Treat Analysis
S Similar Baseline
B Blinding
E Equal Treatment
E Equivalence to your patient


Xiong GL, Adams J. FRISBEE: Does the study fly in the face of evidence-based medicine? The Journal of Family Practice. 2007 Dec;6(12).  Available from:

FRISBEE is great for randomized control trials. See one of the links below if you are using a systematic review. They websites have systematic review evaluation worksheets.

Help to Determine the Validity for non-RCT Research Articles or Clinical Guidelines

Supplementary Resources

Number Needed to Treat (NNT)

  • NNT = number of patients needed to treat in order to prevent one bad outcome
  • NNT = 1/ARR
  • ARR = CER - EER
  • Number Needed to Harm (NNH) is calculated the same way as NNT
  • If a research study had non-statistically significant results, it is not appropriate to calculate NNT.
  • Should be calculated for binary results (MIs versus no MIs).
  • Students should state if is not appropriate to calculate NNT.
  • NNT for a study is always for a specific time period.
  • NNT does not consider baseline risk.
  • NNT can be calculated from data, odds ratios, RRR, and prevalence.
  • It is not necessary to have a placebo. For example, you could be comparing to medications or treatments.
  • More information -  and

Other Relevant Guides