Jocelyn Raude1,2,3, Patrick Peretti-Watel4,5, Jeremy Ward4,5,6, Claude Flamand7, Pierre Verger4,5. 1. EHESP Rennes, Université Sorbonne Paris Cité, France. 2. Aix Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health, UMR_D 190 Emergence des Pathologies Virales, Marseille, France. 3. UMR PIMIT, INSERM 1187, CNRS 9192, IRD 249. Plateforme Technologique CYROI, Université de La Réunion, Réunion, France. 4. Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France. 5. ORS PACA, Southeastern Health Regional Observatory, Marseille, France. 6. Université Paris-Diderot, CNRS, LIED, Interdisciplinary Laboratory of Tomorrow's Energies, Paris, France. 7. Institut Pasteur de Guyane, Unité d'Epidémiologie, Cayenne, France.
Abstract
BACKGROUND: Although people are likely to underestimate the frequencies of risks to health from common diseases and overestimate those from rare diseases, we still do not know much about reasons for this systematic bias, which is also referred to as "primary bias" in the literature. In this study, we take advantage of a series of large epidemics of mosquito-borne diseases to examine the accuracy of judgments of risk frequencies. In this aim, we assessed the perceived v. observed prevalence of infection by Zika, chikungunya or dengue fever during these outbreaks, as well as their variations among different subpopulations and epidemiological settings. METHODS: We used data drawn from 4 telephone surveys, conducted between 2006 and 2016, among representative samples of the adult population in tropical regions (Reunion, Martinique, and French Guiana). The participants were asked to estimate the prevalence of these infections by using a natural frequency scale. RESULTS: The surveys showed that 1) most people greatly overestimated the prevalence of infection by arbovirus, 2) these risk overestimations fell considerably as the actual prevalence of these diseases increased, 3) the better-educated and male participants consistently yielded less inaccurate risk estimates across epidemics, and 4) these biases in the perception of prevalence of these infectious diseases are relatively well predicted by the probability weighting function developed in the field of behavioral decision making. CONCLUSIONS: These findings suggest that the primary bias, which has been found in laboratory experiments to characterize a variety of probabilistic judgments, equally affects perception of prevalence of acute infectious diseases in epidemic settings. They also indicate that numeracy may play a considerable role in people's ability to transform epidemiological observations from their social environment to more accurate risk estimates.
BACKGROUND: Although people are likely to underestimate the frequencies of risks to health from common diseases and overestimate those from rare diseases, we still do not know much about reasons for this systematic bias, which is also referred to as "primary bias" in the literature. In this study, we take advantage of a series of large epidemics of mosquito-borne diseases to examine the accuracy of judgments of risk frequencies. In this aim, we assessed the perceived v. observed prevalence of infection by Zika, chikungunya or dengue fever during these outbreaks, as well as their variations among different subpopulations and epidemiological settings. METHODS: We used data drawn from 4 telephone surveys, conducted between 2006 and 2016, among representative samples of the adult population in tropical regions (Reunion, Martinique, and French Guiana). The participants were asked to estimate the prevalence of these infections by using a natural frequency scale. RESULTS: The surveys showed that 1) most people greatly overestimated the prevalence of infection by arbovirus, 2) these risk overestimations fell considerably as the actual prevalence of these diseases increased, 3) the better-educated and male participants consistently yielded less inaccurate risk estimates across epidemics, and 4) these biases in the perception of prevalence of these infectious diseases are relatively well predicted by the probability weighting function developed in the field of behavioral decision making. CONCLUSIONS: These findings suggest that the primary bias, which has been found in laboratory experiments to characterize a variety of probabilistic judgments, equally affects perception of prevalence of acute infectious diseases in epidemic settings. They also indicate that numeracy may play a considerable role in people's ability to transform epidemiological observations from their social environment to more accurate risk estimates.
Entities:
Keywords:
perceived prevalence; primary bias; probability weighting function; white male effect