Studies have consistently shown that the way side effect information is reported, namely the combination of verbal descriptors and numerical probabilities (1-in-X format), can cause overestimation...Show moreStudies have consistently shown that the way side effect information is reported, namely the combination of verbal descriptors and numerical probabilities (1-in-X format), can cause overestimation of the occurrence rate. This study looked into whether a singular or distributional mode of thinking may cause overestimation as well. The sample consisted of 134 people. Respondents estimated the chance of side effects occurring for four frequency rates: up to 1 in 10, up to 1 in 100, up to 1 in 1,000 and up to 1 in 10,000. In the singular condition, respondents had to estimate the chance that they themselves would experience a side effect. In the distributional condition, they had to estimate that chance for ‘someone’. The mean estimates for the four frequency rates were compared between the two groups. We expected that the singular group would have lower means (i.e. overestimate less), because that group estimates for themselves. That group could be affected by optimistic bias, which has been shown to cause people to estimate their personal risk as lower as that of others. None of the group difference were significant at an alpha level of 5%. Furthermore, the results were inconclusive, as the distributional group had overestimated less for two of the four frequency rates. Oher studies have shown the effect of optimistic bias on the singular mode of thinking, but this was for general risk of negative events. Further research has to show whether this effect translates to side effect risk estimations.Show less
