Table 4.
Performance of several databases and database combinations in terms of sensitivity and precision
| # 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 |
aOverall recall: The total number of included references retrieved by the databases divided by the total number of included references retrieved by all databases
bMedian recall: The median value of recall per review
cMinimum recall: The lowest value of recall per review
dPercentage 100% recall: The percentage of reviews for which the database combination retrieved all included references
ePrecision: The number of included references divided by the total number of references retrieved
fNumber Needed to Read: The total number of references retrieved divided by the number of included references