Improving public interpretation of probabilistic test results: distributive evaluations

Stefania Pighin; Michel Gonzalez; Lucia Savadori; Vittorio Girotto

doi:10.1177/0272989X14536268

Improving public interpretation of probabilistic test results: distributive evaluations

Med Decis Making. 2015 Jan;35(1):12-5. doi: 10.1177/0272989X14536268. Epub 2014 May 19.

Authors

Stefania Pighin¹, Michel Gonzalez², Lucia Savadori¹, Vittorio Girotto³

Affiliations

¹ Department of Cognitive Sciences and Education, University of Trento, Trento, Italy (SP, LS)
² Laboratory of Cognitive Psychology, CNRS and Aix-Marseille University, Marseille, France (MG)
³ Laboratory of Experimental Economics, University IUAV of Venice, Venice, Italy (VG)

PMID: 24842952
DOI: 10.1177/0272989X14536268

Abstract

Health service users err in posttest probability evaluations. Here we document for the first time that users succeed when they reason about numbers of cases and make distributive evaluations. A sample of women interested in prenatal testing incorrectly evaluated the posttest probability that a given fetus had an anomaly, but regardless of their numeracy level, they correctly apportioned the cases for and against that hypothesis. This finding shows that health service users are not doomed to fail in dealing with single-case probabilities and suggests that probabilistic data can be used effectively for communicating test results.

Keywords: distributive evaluation; natural frequencies; numeracy; prenatal diagnosis; risk communication.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Communication*
Consumer Health Information
Decision Making
Female
Humans
Mathematics*
Prenatal Diagnosis / psychology*
Probability*
Risk Assessment*