Table 2.
Cochrane Collaboration tool for assessing risk of bias
| First author and year | Random sequence generation | Allocation concealment | Blinding of participants and personal | Blinding of outcome assessment | Incomplete outcome data | Selective reporting | Other bias | Overall Risk of Bias |
|---|---|---|---|---|---|---|---|---|
| Benton et al. [16] | H | H | H | L | L | L | L | H |
| Cole et al. [17] | L | L | U | L | L | L | L | L |
| Cole et al. [18] | L | L | L | L | L | L | L | L |
| Cole et al. [19] | U | U | U | L | U | L | U | U |
| Corondado et al. [20] | L | U | U | L | L | L | L | L# |
| Denters et al. [21] | L | L | U | U | L | U | U | U |
| Deutekom et al. [22] | L | L | L | U | L | L | L | L |
| Gupta et al. [23] | L | L | L | L | L | L | L | L |
| Hewitson et al. [24] | L | L | L | L | L | L | L | L |
| Hirst et al. [25] | L | L | L | L | L | U | L | L |
| Hughes et al. [26] | H | H | U | U | H | U | H | H |
| King et al. [27] | U | U | U | L | L | U | H | H |
| King et al. [28] | U | U | U | L | L | U | L | U |
| Libby et al. [29] | L | L | L | L | U | L | L | L |
| Lo et al. [30] | L | U | U | L | L | U | L | U |
| McGregor et al. [31] | U | L | L | L | L | L | L | L |
| Moss et al. [32] | L | L | U | L | L | L | L | L |
| Myers et al. [33] | U | U | L | L | U | L | L | U |
| Neter et al. [34] | L | L | U | L | L | L | L | L |
| O'Carroll et al. [35] | L | L | U | L | L | L | L | L |
| Robinson et al. [36] | U | U | U | L | L | U | L | U |
| Santare et al. [37] | L | L | U | U | L | U | L | U |
| van Roon, [38] | L | L | U | L | U | U | L | U |
| van Rossum et al. [39] | L | L | L | U | L | L | L | L |
| Verne et al. [40] | U | U | L | U | L | U | U | U^ |
| Wardle et al. [41] (1) | L | L | L | L | L | L | L | L |
| Wardle et al. [41] (2) | L | L | L | L | L | L | L | L |
| Wardle et al. [41] (3) | L | L | L | L | L | L | L | L |
| Wardle et al. [41] (4) | L | L | L | L | L | U | U | L |
| Watson et al. [42] | L | U | U | L | L | L | L | L |
| White et al. [43] | U | U | U | L | L | L | L | U* |
| Zajac et al. [44] | L | L | L | U | L | L | H | H¥ |
| Zubero et al. [45] | L | L | L | L | L | U | L | L |
L = low, U = unclear, H = high
#Risk of bias is high for the email intervention as not randomly assigned
^Risk of bias is suggested to be high for the self- versus lab-analyzed stool sample intervention as it is much less likely that participants would return self-analyzed negative results
*Risk of bias is suggested to be high for the outdoor advertising intervention implemented in White et al. 2015 because participants not randomly allocated
¥Zajac et al., 2010 reports on the same sample as Cole et al., 2007 and was therefore deemed high risk of bias