Table 7

Formulae for calculating the sensitivity, specificity, precision, and accuracy of searches for detecting sound clinical studies



Manual Review (Hand search)





Meets Criteria
Does Not Meet Criteria

Search Terms
Detected
a
b

Not detected
c
d


a + c
b + d

a = true positives, articles found by the search term meet the criteria for purpose category (e.g., treatment) and methodologic rigor (i.e., "pass")

b = false positives, articles found by the search term do not meet the criteria for purpose category and methodologic rigor

c = false negatives, articles not found by the search term but did meet the criteria for purpose category and methodologic rigor

d = true negatives, articles not found by the search term and did not meet the criteria for purpose category and methodologic rigor

Sensitivity = a/(a+c); Precision = a/(a+b); Specificity = d/(b+d);

Accuracy = (a+d)/(a+b+c+d).

All articles classified during the manual review of the literature, n = (a+b+c+d).

Wilczynski et al. BMC Medical Informatics and Decision Making 2005 5:20   doi:10.1186/1472-6947-5-20