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Table 4 Screening, extraction and risk of bias assessment in the included systematic reviews (the HTA data were collected for this study; all other data are from Page et al. [1], i.e. the data collected for 300 systematic reviews for a single month in 2004 and 2014)

From: Nature and reporting characteristics of UK health technology assessment systematic reviews

Characteristic 2004 n = 300 [1] HTA 2004 n = 23 HTA 2014 n = 30 Cochrane 2014 n = 45 [1] 2014 n = 300 [1]
Screening
By at least two authors NR 14 (61%) 22 (73%) 44 (98%) 200 (67%)
By one author, with a sample screened by a second NR 2 (9%) 3 (10%) 1 (2%) 7 (2%)
By one author only NR 2 (9%) 1 (3%) 0 (0%) 6 (2%)
Not reported / Unclear NR 5 (22%) 4 (13%) 0 (0%) 87 (29%)
Empty review (no included / eligible studies) NR 0/23 (0%) 2/30 (7%) 3/45 (7%) 4/300 (1%)
Extraction NR n = 23 n = 28 n = 42 n = 296
By at least two authors NR 4 (17%) 5 (18%) 41 (98%) 163 (55%)
By one author, with data verified by a second NR 14 (61%) 19 (68%) 0 (0%) 29 (10%)
By one author only NR 1 (4%) 2 (7%) 0 (0%) 7 (2%)
Not reported / Unclear NR 4 (17%) 2 (7%) 1 (2%) 97 (33%)
Quality assessment - (67%) 23 (100%) 28 (100%) 42 (100%) 206 (70%)
By at least two authors NR 5 (22%) 10 (36%) 37 (88%) 121/206 (59%)
By one author, with data verified by a second NR 11 (48%) 12 (43%) 0 (0%) 6/206 (3%)
By one author only NR 1 (4%) 0 (0%) 0 (0%) 3/206 (1%)
Not reported NR 6 (26%) 6 (21%) 5 (12%) 76/206 (37%)
Risk of bias / quality assessment tool
Cochrane (or modification) NR 2 (9%) 12 (43%) 37 (88%) 77 (37%)
Jadad NR 4 (17%) 0 (0%) 0(0%) 33 (11%)
Newcastle-Ottowa NR 0 0 (0%) 1 (2%) 17 (8%)
QUADAS, QUADAS-2 NR 1 (4%) 5 (18%) 0 (0%) 8 (4%)
Own NR 2 (9%) 3 (11%) 2 (5%) 38 (18%)
Other NR 14 (61%)a 9 (32%)a 3 (7%) 53 (26%)
Not reported NR 1 (4%) 1 (4%) 0 (0%) 6 (3%)
Selective reportingb NR 0 10/28 (36%) 36/42 (86%) 70 (24%)
  1. HTA Health Technology Assessment aEspecially CRD criteria, which are arguably as appropriate to UK HTA as the Cochrane risk of bias tool is to Cochrane reviews. bNot always applicable, e.g. diagnostics: it is not a field in the QUADAS tool; NR Not reported