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. Author manuscript; available in PMC: 2022 Jun 17.
Published in final edited form as: Appetite. 2021 May 11;164:105277. doi: 10.1016/j.appet.2021.105277

Table 2.

Study characteristics regarding design, analytic reproducibility, and risks of bias. Binary and categorical variables are reported as “count (percentage)”. Continuous variables are reported as “median (first quartile, third quartile)”.

Characteristic All studies (k = 100) Published studies (k = 17) Unpublished studies (k = 83)
Design
 Between-subjects RCT 72 (72%) 16 (94%) 56 (67%)
 Within-subject RCT 1 (1%) 1 (6%) 0 (0%)
 Cluster RCT 2 (2%) 0 (0%) 2 (2%)
 Between-subjects NRCT 21 (21%) 0 (0%) 21 (25%)
 Within-subject UCT 4 (4%) 0 (0%) 4 (5%)
Outcome measurement
 Direct behavioral measure 2 (2%) 1 (6%) 1 (1%)
 Self-reported past behavior 41 (41%) 1 (6%) 40 (48%)
 Intended future behavior 57 (57%) 15 (88%) 42 (51%)
Percent missing data 7.5 (7.3, 42) 0 (0, 7.95) 13.2 (7.5, 59.75)
 Not reported 23 (23%) 2 (12%) 21 (25%)
Exchangeability
 Low risk of bias 52 (52%) 16 (94%) 36 (43%)
 Medium risk of bias 9 (9%) 1 (6%) 8 (10%)
 High risk of bias 29 (29%) 0 (0%) 29 (35%)
 Unclear 10 (10%) 0 (0%) 10 (12%)
Avoidance of social desirability bias
 Low risk of bias 13 (13%) 6 (35%) 7 (8%)
 Medium risk of bias 14 (14%) 5 (29%) 9 (11%)
 High risk of bias 68 (68%) 6 (35%) 62 (75%)
 Unclear 5 (5%) 0 (0%) 5 (6%)
External generalizability
 Low risk of bias 36 (36%) 10 (59%) 26 (31%)
 Medium risk of bias 28 (28%) 7 (41%) 21 (25%)
 High risk of bias 15 (15%) 0 (0%) 15 (18%)
 Unclear 21 (21%) 0 (0%) 21 (25%)
Preregistered
 Yes 25 (25%) 2 (12%) 23 (28%)
 No 75 (75%) 15 (88%) 60 (72%)
Public data
 Yes 53 (53%) 5 (29%) 48 (58%)
 No 47 (47%) 12 (71%) 35 (42%)
Public code
 Yes 22 (22%) 4 (24%) 18 (22%)
 No 78 (78%) 13 (76%) 65 (78%)
Overall lowest risk of bias
 Yes 12 (12%) 9 (53%) 3 (4%)
 No 88 (88%) 8 (47%) 80 (96%)

k: Number of studies in subset. RCT: randomized controlled trial. NRCT: non-randomized controlled trial. UCT: uncontrolled trial (i.e., no separate control group) but with subjects serving as own controls.

a:

For studies in which missing data was unreported but the outcome was measured in the same session as the intervention, we coded missing data as 0. Details on the risk-of-bias categories are provided in the Supplement.