Table 1 Protocol characteristics comparison between published protocols and unpublished protocols (N = 397)
Protocol’s characteristics | Total ( N = 397) | Published protocols ( N = 244) | Unpublished protocols ( N = 153) | p -value |
|---|---|---|---|---|
Information of corresponding author | ||||
 Scopus’s h-index of corresponding author | 0.118c | |||
  Value | 8 (14.5) | 9.5 (15.5) | 5 (3.0) |  |
 Corresponding author based in developed countries | 0.019a | |||
  Yes | 320 (80.6) | 206 (84.4) | 114 (74.5) |  |
  No | 77 (19.4) | 38 (15.6) | 39 (25.5) |  |
 Corresponding author based in English-speaking countries | 0.006a | |||
  Yes | 237 (59.7) | 159 (65.2) | 78 (51.0) |  |
  No | 160 (40.3) | 85 (34.8) | 75 (49.0) |  |
 Corresponding author is the first author | 0.278a | |||
  Yes | 301 (75.8) | 180 (73.8) | 121 (79.1) |  |
  No | 96 (24.2) | 64 (26.2) | 32 (20.9) |  |
 Country of corresponding authors | 0.033b | |||
  UK | 79 (19.9) | 58 (23.8) | 21 (13.7) |  |
  Australia | 62 (15.6) | 44 (18.0) | 18 (11.8) |  |
  Canada | 46 (11.6) | 28 (11.5) | 18 (11.8) |  |
  USA | 47 (11.8) | 26 (10.7) | 21 (13.7) |  |
  China | 24 (6.0) | 14 (5.7) | 10 (6.5) |  |
  Others | 139 (35.0) | 74 (30.3) | 65 (42.5) |  |
 Other characteristics | ||||
 Number of authors registered in protocols | 0.333c | |||
  Value | 5 (3) | 5 (3) | 4 (3) |  |
 External co-worker | 0.909a | |||
  Yes | 114 (28.7) | 71 (29.1) | 43 (28.1) |  |
  No | 283 (71.3) | 173 (70.9) | 110 (71.9) |  |
 Registered database | 0.186b | |||
  Cochrane only | 86 (21.7) | 49 (20.1) | 37 (24.2) |  |
  PROSPERO only | 100 (25.2) | 72 (29.5) | 28 (18.3) |  |
  JBI only | 51 (12.8) | 28 (11.5) | 23 (15.0) |  |
  SJR | 16 (4.0) | 10 (4.1) | 6 (3.9) |  |
  Others | 23 (5.8) | 12 (4.9) | 11 (7.2) |  |
  Duo register (a) | 121 (30.5) | 73 (29.9) | 48 (31.4) |  |
 Study funding | 0.029b | |||
  No funding support | 180 (45.4) | 104 (42.6) | 76 (49.7) |  |
  Internal fund only | 74 (18.6) | 40 (16.4) | 34 (22.2) |  |
  Having external fund (with/without internal fund) | 143 (36.0) | 100 (41.0) | 43 (28.1) |  |
 Protocol was updated | 0.033a | |||
  Yes | 118 (29.7) | 82 (33.6) | 36 (23.5) |  |
  No | 279 (70.3) | 162 (66.4) | 117 (76.5) |  |
 Type of systematic review | 0.667b | |||
  Effectiveness | 311 (78.3) | 191 (78.3) | 120 (78.4) |  |
  Experiential or qualitative | 22 (5.5) | 12 (4.9) | 10 (6.5) |  |
  Etiology or risk | 21 (5.3) | 11 (4.5) | 10 (6.5) |  |
  Diagnostic test accuracy | 16 (4.0) | 11 (4.5) | 5 (3.3) |  |
  Others | 27 (6.8) | 19 (7.8) | 8 (5.2) |  |