At 11.30 Philip Ebert (Stirling) will present on "End user and forecaster interpretations of the European avalanche danger scale: a study of avalanche probability judgements in Scotland"

at 12.15 Martina Barjakova (University of Milano-Bicocca) will present on "Delayed synergies are harder to see: an experimental investigation of factors influencing synergistic judgements of health risks"

Abstracts below:

End user and forecaster interpretations of the European avalanche danger scale: a study of avalanche probability judgements in Scotland

We investigate Scottish end users’ risk perception ( N = 678) of the five point European Avalanche Danger Scale by eliciting numerical probability judgements. Our main findings are that end users’ risk perception of the danger scale increases linearly rather than exponentially (as intended by the avalanche services), confirming recent findings by Morgan, Haegeli, Finn, and Mair (2023) who used a different scale and a North American user group. Second, we find significant differences in the perceived probability of avalanches relative to a given avalanche danger level depending on whether respondents are asked by a frequency or a percentage chance response format. More specifically, we find that a frequency format elicits lower estimates and, in some cases, a higher variance. Third, we find that individual characteristics of end users (such as outdoor sport experience, age, gender, avalanche education, and having experienced an avalanche) has little explanatory power to predict their interpretation of the avalanche danger scale. Finally, using a small scale sample (N = 19) of professional avalanche forecasters in Scotland, we find that there is little expected and actual overlap between end users and professional forecasters in their numerical interpretation of the danger scale. We summarise our findings by identifying important lessons for strategies to improve avalanche risk understanding and its communication.

Delayed synergies are harder to see: an experimental investigation of factors influencing synergistic judgements of health risks

When certain health hazards are combined, they produce synergies. In other words, they lead to risks that are greater than the sum of risks presented by each factor separately. For instance, smoking and radon exposure interact synergistically to increase lung cancer risk. Without doubt, how people judge such risk combinations is important – and previous research showed mostly underestimation of synergistic risks. Our previous research instead suggests that people are better at judging certain synergistic risks as such than others. In the current pre-registered study, we aim to understand why this is the case. In particular, we experimentally test whether the likelihood of judging a combination of risk factors as synergistic depends on the outcome being immediate or delayed, binary or continuous, or whether knowledge about the outcome plays a role. We find that synergistic judgements are much more likely for immediate outcomes compared to the delayed ones. Thanks to the structure of our data, we are also able to shed light on the possible mechanism for this. In particular, our data suggest that this result is due to the difference in how much weight people give to the single risk factors for immediate vs delayed outcomes, not to how they evaluate the combination of risk factors. Our study furthermore tests for the effects of format of the task. We find that synergistic judgements are more likely if natural frequencies and partitive probabilities are used, as opposed to non-partitive (single-case) probabilities. These results have important implications for communications concerning synergistic health risks.