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Table 1 Definitions and formulae for the search performance metrics used to evaluate the complementary approaches

From: LOCATE: a prospective evaluation of the value of Leveraging Ongoing Citation Acquisition Techniques for living Evidence syntheses

Performance metrica Definition and formula
Proportion of studies missedb Number of records not identified by the search, out of the total identified by the reference standard:
# relevant studies complementary search approach/# studies included using the reference standard approach × 100
Precision (specificity) The number of relevant studies identified by the search, relative to the total number of records identified by the search:
# relevant studies identified/# records retrieved by the search × 100
Sensitivity The number of records correctly identified by the search, relative to the total number of relevant studies that exist (identified by the reference standard):
# records retrieved by the search/total number of potentially eligible articles that may exist × 100
Number needed to read (NNR) The number of records identified by the search that need to be screened to locate one included study:
  1. aMetrics were calculated for each of the complementary search approaches and compared to the reference standard approach
  2. bWe planned to also record any additional studies located by a complementary method that were not located via the reference standard approach, but this was not applicable