Omission bias and pertussis vaccination.
BACKGROUND
Several laboratory studies have suggested that many people favor potentially harmful omissions over less harmful acts. The authors studied the role of this omission bias in parents' decisions whether to vaccinate their children against pertussis.


METHODS
Two hundred mail surveys were sent to subscribers to a magazine that had published articles favoring and opposing pertussis vaccination. Subjects were asked about their beliefs about the vaccine and the disease, and whether they had vaccinated their own children or planned to, and they were given test items to identify omission bias in their reasoning.


RESULTS
One hundred and three subjects (52%) responded to the survey. Respondents who reported they did not or would not allow their children to be vaccinated (n = 43; 41%) were more likely to believe that vaccinating was more dangerous than not vaccinating (p < 0.001). They were also more likely to exhibit omission bias (p = 0.004), holding constant their stated beliefs about the danger of the vaccine.


CONCLUSIONS
Omission bias plays a role in decisions not to vaccinate with pertussis vaccine, beyond the role played by belief about the risk of vaccination.
Department of Psychology, University of Pennsylvania School of Arts and Sciences.
D A
DA
Asch
J
J
Baron
J C
JC
Hershey
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Kunreuther
J
J
Meszaros
I
I
Ritov
M
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Spranca
D000328:Adult; D002675:Child, Preschool; D003657:Decision Making; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000009:adverse effects; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D010290:Parents / Q000193:education / Q000523:psychology; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D011287:Prejudice; D012309:Risk-Taking; D011795:Surveys and Questionnaires; D014481:United States
D015721:Diphtheria-Tetanus-Pertussis Vaccine