Fig. 2From: The absence of data on driving under the influence of alcohol in road traffic studies: a scoping review of non-randomized studies with vote counting based on the direction of effects of alcohol policiesSummary of the risk of bias assessmentNotes. Risk of bias domains were as follows: D1, study question; D2, eligibility criteria and study population; D3, representativeness of study participants; D4, participants' enrollment; D5, sample size; D6, description and implementation of the intervention; D7, outcomes measures; D8, statistical analysis; and D9, multiple outcome measures. Studies having a low risk of bias in a specific domain were represented by a green plus sign. Those studies judged as having some concern for bias in a specific domain were represented by a red negative signBack to article page