Deliberative Disjunction: Expert and Public Understanding of Outcome Uncertainty

Abstract

Many environmental and risk management decisions are made jointly by technical experts and members of the public. Frequently, their task is to select from among management alternatives whose outcomes are subject to varying degrees of uncertainty. Although it is recognized that how this uncertainty is interpreted can significantly affect decision-making processes and choices, little research has examined similarities and differences between expert and public understandings of uncertainty. We present results from a web-based survey that directly compares expert and lay interpretations and understandings of different expressions of uncertainty in the context of evaluating the consequences of proposed environmental management actions. Participants responded to two hypothetical but realistic scenarios involving trade-offs between environmental and other objectives and were asked a series of questions about their comprehension of the uncertainty information, their preferred choice among the alternatives, and the associated difficulty and amount of effort. Results demonstrate that experts and laypersons tend to use presentations of numerical ranges and evaluative labels differently; interestingly, the observed differences between the two groups were not explained by differences in numeracy or concerns for the predicted environmental losses. These findings question many of the usual presumptions about how uncertainty should be presented as part of deliberative risk- and environmental-management processes.

Making sense of uncertainty: advantages and disadvantages of providing an evaluative structure

“…In other words, participants appeared to weigh the overall uncertainty more when this aspect of uncertainty was made salient through the use of evaluative labels. Interestingly, as we have reported elsewhere (Gregory et al 2011), people tended to choose in a similar manner when the label and range were present. This was true for both more and less numerate participants.…”

“…Thus, choice is a primary dependent variable. As we report in a companion paper (Gregory et al 2011), laypeople, as opposed to experts, tended to focus on evaluative labels, even when presented with a numerical uncertainty range. We expect the evaluative labels to be an important determinant of choice.…”

“…Note: Confidence intervals for the proportions were calculated using Wilson's method (Wilson 1927 As expected, participants were more likely to choose the option with the highest confidence or the compromise option when an evaluative label was present. The similarity in the pattern of choices for the evaluative label only and the combined condition suggests that laypeople tended to use the evaluative labels more than the numeric range (also see companion paper, Gregory et al 2011). In the range-only condition, the majority of the participants chose the option with the highest best estimate but the lowest confidence (largest range).…”

Understanding and minimizing environmental impacts of the Belt and Road Initiative

“…Deliberative decision‐making tools for multivariate problems are well established and can help reduce impact associated with infrastructure development (Gregory et al. ). The first step is to identify where these impacts may occur so that all planning options can be considered.…”

Using decision pathway surveys to inform climate engineering policy choices

“…A second design consideration is that questions must be cognitively appropriate because the constructive processes underlying a response can be highly sensitive to how a problem is presented (43,44). A third consideration is that the survey design must strike a balance between being concise and informative: enough information needs to be provided so people feel they are sufficiently well informed to answer the questions asked of them yet not overwhelmed with unnecessary detail.…”