Randomization and blinding
Participants were randomly assigned into three different groups before the assessment: U-CPR; T-CPR; and V-CPR. During randomization, the permuted block technique was used with a 1:1:1 ratio. After randomization, study participants were informed about their allocated group, but were blinded to the purpose of the study. The dispatchers, assessors and the operator were informed about their tasks in the different groups but were blinded to the study design and the outcomes.