Improving public interpretation of probabilistic test results: distributive evaluations.
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.
Department of Cognitive Sciences and Education, University of Trento, Trento, Italy (SP, LS)
Stefania
S
Pighin
Laboratory of Cognitive Psychology, CNRS and Aix-Marseille University, Marseille, France (MG)
Michel
M
Gonzalez
Department of Cognitive Sciences and Education, University of Trento, Trento, Italy (SP, LS)
Lucia
L
Savadori
Laboratory of Experimental Economics, University IUAV of Venice, Venice, Italy (VG)
Vittorio
V
Girotto
D003142:Communication; D054626:Consumer Health Information; D003657:Decision Making; D005260:Female; D006801:Humans; D008433:Mathematics; D011296:Prenatal Diagnosis / Q000523:psychology*; D011336:Probability; D018570:Risk Assessment
distributive evaluation; natural frequencies; numeracy; prenatal diagnosis; risk communication