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Table 1 Two by two contingency table comparing filter to ‘reference standard’

From: Glomerular disease search filters for Pubmed, Ovid Medline, and Embase: a development and validation study

Filter (consisting of single or combined terms)

Manual review of each article

 

Articles relevant to glomerular disease

Articles not relevant to glomerular disease

Article identified

a

b

Article not identified

c

d

  1. Sensitivity = a/(a + c): proportion of all articles with information on glomerular disease in the reference set that are retrieved by the filter (also called recall in information retrieval studies).
  2. Specificity = d/(b + d): proportion of all articles without information on glomerular disease in the reference set that are correctly not retrieved by the filter.
  3. Precision = a/(a + b): proportion of all articles retrieved by the filter with information on glomerular disease (also referred to as positive predictive value in diagnostic test terminology).
  4. Accuracy = (a + d)/(a + b + c + d): proportion of all articles dealt with correctly by filter.