Table 2.
Knowledge synthesis method characteristics
| Method characteristics (n = 438)a | Count (%) | ||
|---|---|---|---|
| A priori protocol and review design | A priori protocol | Use of a protocol mentioned | 66 (15.1) |
| Published | 40 (9.1) | ||
| Registered | 25 (5.7) | ||
| Available upon request | 6 (1.4) | ||
| Not reported | 301 (68.7) | ||
| Research question | Clearly reported | 437 (99.8) | |
| Unclear/inferred | 1 (0.2) | ||
| Eligibility criteria | Clearly reported | 430 (98.2) | |
| Unclear/inferred | 1 (0.2) | ||
| Not reported | 7 (1.6) | ||
| Identifying relevant studies | Databases searched | Searched more than one database | 407 (92.9) |
| Searched only one database | 29 (6.6) | ||
| Not reported | 2 (0.5) | ||
| Search string | Complete literature search | 207 (47.3) | |
| MeSH terms only | 173 (39.5) | ||
| Not reported | 58 (13.2) | ||
| Additional search strategy | Scanned references | 309 (70.5) | |
| Grey literature searched | 270 (61.6) | ||
| Consulted topic experts | 80 (18.3) | ||
| Consulted librarian | 67 (15.3) | ||
| Performed updated search | 62 (14.2) | ||
| Manually searched selected journals | 37 (8.4) | ||
| Limits applied | Limited by study design | 291 (66.4) | |
| Limited by language | 147 (33.6) | ||
| Limited by date | 135 (30.8) | ||
| Other limits (e.g., age, humans) | 129 (29.5) | ||
| Study selection | Title & abstract screening | Two or more independent reviewers | 285 (65.1) |
| One reviewer and one verifier | 9 (2.1) | ||
| One reviewer only | 16 (3.7) | ||
| Done but unclear number of reviewers | 92 (21.0) | ||
| Not reported | 36 (8.2) | ||
| Full-text screening | Two or more independent reviewers | 282 (64.4) | |
| One reviewer and one verifier | 11 (2.5) | ||
| One reviewer only | 7 (1.6) | ||
| Done but unclear number of reviewers | 105 (24.0) | ||
| Not reported | 33 (7.5) | ||
| Study flow | Completely in PRISMA-like flow diagram | 374 (85.4) | |
| Completely in text/table only | 20 (4.6) | ||
| Partially reported | 15 (3.4) | ||
| Not reported | 29 (6.6) | ||
| Data abstraction & quality assessment | Data abstraction | Two or more independent reviewers | 238 (54.3) |
| One reviewer and one verifier | 94 (21.5) | ||
| One reviewer only | 8 (1.8) | ||
| Done but unclear number of reviewers | 75 (17.1) | ||
| Not reported | 23 (5.3) | ||
| Quality appraisal | Two or more independent reviewers | 181 (41.3) | |
| One reviewer and one verifier | 21 (4.8) | ||
| One reviewer only | 9 (2.1) | ||
| Done but unclear number of reviewers | 133 (30.4) | ||
| Not reported | 94 (21.5) | ||
a18 out of 456 NMAs did not provide details of their knowledge synthesis method