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Table 4 Performance of several databases and database combinations in terms of sensitivity and precision

From: Optimal database combinations for literature searches in systematic reviews: a prospective exploratory study

  # results # includes (N = 1746) Overall recalla Median recallb Minimum recallc Percentage 100% recalld Precisione Number needed to readf
Embase (EM) 85,521 1500 85.9% 87.3% 45.8% 13.8% 1.8% 57
MEDLINE (ML) 56,340 1375 78.8% 82.9% 50.0% 8.6% 2.4% 41
Web of Science (WoS) 48,561 1189 68.1% 72.5% 13.2% 6.9% 2.4% 41
Google Scholar (GS) 10,342 601 34.4% 38.0% 8.3% 5.2% 5.8% 17
EM-ML 100,444 1621 92.8% 94.6% 66.7% 24.1% 1.6% 62
EM-WoS 104,444 1585 90.8% 93.8% 57.9% 27.6% 1.5% 66
EM-GS 91,411 1570 89.9% 93.3% 65.8% 25.9% 1.7% 58
ML-WoS 75,263 1481 84.8% 87.1% 60.0% 15.5% 2.0% 51
ML-GS 62,230 1459 83.6% 89.8% 63.2% 15.5% 2.3% 43
WoS-GS 54,451 1320 75.6% 85.7% 23.7% 13.8% 2.4% 41
EM-ML-GS 106,334 1674 95.9% 97.4% 78.9% 41.4% 1.6% 64
EM-ML-WoS 119,367 1674 95.9% 97.1% 71.1% 37.9% 1.4% 70
EM-WoS-GS 110,334 1638 93.8% 98.1% 65.8% 44.8% 1.5% 67
ML-WoS-GS 81,153 1528 87.5% 92.6% 70.0% 29.3% 1.9% 53
EM-ML-GS-WoS 125,257 1716 98.3% 100.0% 78.9% 74.1% 1.4% 73
  1. aOverall recall: The total number of included references retrieved by the databases divided by the total number of included references retrieved by all databases
  2. bMedian recall: The median value of recall per review
  3. cMinimum recall: The lowest value of recall per review
  4. dPercentage 100% recall: The percentage of reviews for which the database combination retrieved all included references
  5. ePrecision: The number of included references divided by the total number of references retrieved
  6. fNumber Needed to Read: The total number of references retrieved divided by the number of included references