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Table 1 Number of systematic reviews that searched for and included non-English studies, unpublished studies, and dissertations

From: Grey literature in systematic reviews: a cross-sectional study of the contribution of non-English reports, unpublished studies and dissertations to the results of meta-analyses in child-relevant reviews

Review Group Total number of SRs Number that searched for study typea
N (%)
Number that included study typea
N (%)
Total number of studies included in SR Total number of study typea included
N (%)
Non-English Studies
 ARI 57 57 (100) 11 (19.3) 398 28 (7.0)
 ID 38 38 (100) 4 (10.5) 238 6 (0.8)
 DPLP 34 33 (97.1) 0 (0.0) 144 0 (0.0)
 Total 129 128 (99.2) 15 (11.7) 780 34 (4.4)
Unpublished studies
 ARI 57 55 (96.5) 5 (7.3) 398 11 (2.8)
 ID 38 38 (100) 2 (5.3) 238 3 (1.3)
 DPLP 34 31 (91.2) 1 (3.2) 144 1 (0.7)
 Total 129 124 (96.1) 8 (5.6) 780 15 (1.9)
Dissertations
 ARI 57 5 (8.8) 1 (20.0) 398 2 (0.5)
 ID 38 1 (2.6) 1 (100) 238 2 (0.8)
 DPLP 34 22 (64.7) 7 (31.8) 144 11 (7.6)
 Total 129 28 (21.7) 9 (32.1) 780 15 (1.9)
  1. ARI acute respiratory infections, ID infectious diseases, DPLP developmental, psychosocial and learning problems, SR systematic review
  2. astudy type refers to Non-English, unpublished, or dissertation