Confirmatory Bias in Health Decisions: Evidence from the Mmr-Autism Controversy

36 Pages Posted: 24 Feb 2020 Last revised: 25 Feb 2023

See all articles by Mengcen Qian

Mengcen Qian

Fudan University - School of Public Health

Shin-Yi Chou

Lehigh University

Ernest Lai

Lehigh University - Department of Economics

Date Written: February 2020

Abstract

Since Wakefield et al. (1998), the public was exposed to mixed information surrounding the claim that measles-mumps-rubella vaccine causes autism. A persistent trend to delay the vaccination during 1998–2011 in the US was driven by children of college-educated mothers, suggesting that these mothers held biases against the vaccine influenced by the early unfounded claim. Consistent with confirmatory bias, exposures to negative information about the vaccine strengthened their biases more than exposures to positive information attenuated them. Positive online information, however, had strong impacts on vaccination decisions, suggesting that online dissemination of vaccine-safety information may help tackle the sticky misinformation.

Suggested Citation

Qian, Mengcen and Chou, Shin-Yi and Lai, Ernest, Confirmatory Bias in Health Decisions: Evidence from the Mmr-Autism Controversy (February 2020). NBER Working Paper No. w26772, Available at SSRN: https://ssrn.com/abstract=3543295

Mengcen Qian (Contact Author)

Fudan University - School of Public Health

School of Public Health
PO Box 250
Shanghai, 200032
China

Shin-Yi Chou

Lehigh University ( email )

621 Taylor Street
Bethlehem, PA 18015
United States

Ernest Lai

Lehigh University - Department of Economics ( email )

620 Taylor Street
Bethlehem, PA 18015
United States

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