Comparing the standard rating scale and the magnifier scale for assessing risk perceptions

Objective. A new risk perception rating scale ("magnifier scale") was recently developed to reduce elevated perceptions of low-probability health events, but little is known about its performance. The authors tested whether the magnifier scale lowers risk perceptions for low-probability (in 0%-1% magnifying glass section of scale) but not high-probability (> 1%) events compared to a standard rating scale (SRS). Method. In studies 1 (n = 463) and 2 (n = 105), undergraduates completed a survey assessing risk perceptions of high- and low-probability events in a randomized 2 x 2 design: in study 1 using the magnifier scale or SRS, numeric risk information provided or not, and in study 2 using the magnifier scale or SRS, high- or low-probability event. In study 3, hypertension patients at the Philadelphia Veterans Affairs hospital completed a similar survey (n = 222) assessing risk perceptions of 2 self-relevant high-probability events-heart attack and stroke-with the magnifier scale or the SRS. Results. In study 1, when no risk information was provided, risk perceptions for both high- and low-probability events were significantly lower (P < 0.0001) when using the magnifier scale compared to the SRS, but risk perceptions were no different by scale when risk information was provided (interaction term: P = 0.003). In studies 2 and 3, risk perceptions for the high-probability events were significantly lower using the magnifier scale than the SRS (P = 0.015 and P = 0.014, respectively). Conclusions. The magnifier scale lowered risk perceptions but did so for low- and high-probability events, suggesting that the magnifier scale should not be used for assessments of risk perceptions for high-probability events.