Search results by week (27 April–5 July 2009).

A: Number of potentially relevant new records in PubMed at the end of each week, as identified by a simulated historical search (Step 10). B: Number of records identified as relevant after review of all records in A (Step 11). C: Percentage of relevant records in Column B missed when a given search term was not included, with the number of records in parentheses (Step 15). The mean percentages and records are calculated as an arithmetic mean of the weekly values.