Step 3: Assess evidence

Are the results likely to be valid?

Criteria Yes No
Was the assignment of patients to treatment randomized?
Was follow-up of patients sufficiently long and complete?
Were the patients analyzed in the groups to which they were randomized?
Were the patients and clinicians kept blind to treatment?
Were the groups treated equally, apart from the experimental therapy?
Were groups similar at the start of the trial?

Are the results of the study important? What is the magnitude of the treatment effect?

Outcome Present Outcome Absent
Treatment a b
Control c d

Since the treatment in this study increases the possibility of a good event:

Calculate the EER:

Calculate the CER:

Calculate the RBI:

Calculate the ABI:

Calculate the NNT:

What is the precision of the treatment effect?

Calculate the Confidence Interval for the NNT:

EER (Experimental Event Rate) %

CER (Control Event Rate) %

Number of patients in experimental group (Enter from article)

Number of patients in control group (Enter from article)

95% CI for NNT


Explanation of Answer:

Continue to Step 4: Apply the evidence