Skip to main content

Table 1 Contingency table comparing filter to ‘reference set’ and explanation of statistical descriptions

From: Paramedic literature search filters: optimised for clinicians and academics

Filter Manual review of each article  
  Paramedic articles Non-paramedic articles  
Article identified a b a + b
Article not identified c d c + d
  a + c b + d a + b + c + d
  1. Caption: Sensitivity = a/(a + c): proportion of all articles relevant to paramedics in the reference set that are retrieved by the filter. Specificity = d/(b + d): proportion of all articles not relevant to paramedics in the reference set that are correctly not retrieved by the filter. Precision = a/(a + b). NNR = 1/precision: the number of relevant and non-relevant articles that need to be screened in order to find one of relevance