A response to Mandel’s (2019) commentary on Stastny and Lehner (2018)
Journal Title: Judgment and Decision Making - Year 2019, Vol 14, Issue 5
Abstract
Stastny and Lehner (2018) compared the accuracy of forecasts in an intelligence community prediction market to comparable forecasts in analysis reports prepared by groups of professional intelligence analysts. To obtain quantitative probabilities from the analysis reports experienced analysts were asked to read the reports and state what probability they thought the reports implied for each forecast question. These were called imputed probabilities. Stastny and Lehner found that the prediction market was more accurate than the imputed probabilities and concluded that this was evidence that the prediction market was more accurate than the analysis reports. In a commentary, Mandel (2019) took exception to this interpretation. In a re-analysis of the data, Mandel found a very strong correlation between readers’ personal and imputed probabilities. From this Mandel builds a case that the imputed probabilities are little more than a reflection of the readers’ personal views; that they do not fairly reflect the contents of the analysis reports; and therefore, any accuracy results are spurious. This paper argues two points. First, the high correlation between imputed and personal probabilities was not evidence of substantial imputation bias. Rather it was the natural by-product of the fact that the imputed and personal probabilities were both forecasts of the same events. An additional analysis shows a much lower level of imputation bias that is consistent with the original results and interpretation. Second, the focus of Stastny and Lehner (2018) was on the reports as understood by readers. In this context, even if there was substantial imputation bias it would not invalidate accuracy results; it would instead provide a possible causal explanation of those results.
Authors and Affiliations
Paul Lehner and Bradley Stastny
Keywords
Related Articles
- EP ID EP678442
- DOI -
- Views 151
- Downloads 0
The impact of regret and worry on the threshold level of concern for flood insurance demand: Evidence from Dutch homeowners
It has been argued that individuals behave according to a threshold level of concern decision rule when considering protection against risk: if the perceived probability of the risk is below a threshold level, then the l...
The effect of consumer ratings and attentional allocation on product valuations
Online marketplaces allow consumers to leave reviews about the products they purchase, which are visible to potential customers and competitors. While the impact of reviews on valuations of worth and purchasing decisions...
Winning a battle but losing the war: On the drawbacks of using the anchoring tactic in distributive negotiations
In two experiments, we explored the possible drawbacks of applying the anchoring tactic in a negotiation context. In Study 1, buyers who used the anchoring tactic made higher profits, but their counterparts thought their...
A universal method for evaluating the quality of aggregators
We propose a new method to facilitate comparison of aggregated forecasts based on different aggregation, elicitation and calibration methods. Aggregates are evaluated by their relative position on the cumulative distribu...
Decisions in moral dilemmas: The influence of subjective beliefs in outcome probabilities
Previous studies have found that the proportions of people who endorsed utilitarian decisions varied across different variants of the trolley dilemma. In this paper, we explored whether moral choices were associated with...