Perception of Synergistic Risk: Adjusted Anchoring Vignettes for Optimized Measurement

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Principal investigator:

Craig W. Trumbo

Colorado State University



Sample size: 407

Field period: 03/25/2005-03/29/2005


Scientists are finding synergistic combinations for a number of health hazards. The best recognized synergistic health risks involve smoking and radon for cancer, smoking and alcohol for cancer, and smoking and oral contraceptives for heart disease. Recently, family history of coronary heart disease (CHD) has been shown to be synergistic for CHD when combined with several factors, especially smoking. Because synergistic risks can be many times greater than their components, it is important to understand how laypersons view such hazards and to develop effective tools to communicate these risks. The experiment proposed here is designed to 1) test the ability of a message to induce perception of synergistic risk, 2) test the anchored vignette approach for measuring how subjects apply synergistic risk to others, and 3) apply the full adjusted vignette method to test if individuals apply synergistic risk to themselves conditioned on their risk profile.


The primary aim of this project is to demonstrate that PSR can be induced and detected. Success will be determined by a set of tests evaluating the ranking and linearity of vignettes by treatment/control groups and the difference in the calculated individual PSR score across groups and across personal risk conditions (e.g., smokers/nonsmokers) using King's method. Vignettes (V1-4 ) are described in the questionnaire.
H1a : In the control group, respondents will rate risk for vignettes V1
H1b : In the control group, values in H1a (V1
H2a : In the treatment group, respondents will rate risk for vignettes V1
H2b : In the treatment group, values in H2a (V1
H3 : Mean adjusted PSR(treatment) will be greater than mean adjusted PSR(control).

Experimental Manipulations

Sets of vignettes will be provided for two synergistic hazards: radon and smoking for lung cancer and smoking plus family history for coronary heart disease. Respondents will also answer a set of questions on their smoking status, family history for heart disease, and experience with radon. Prior to competing the survey, half of respondents will be exposed to a strong message describing these two synergistic risks. Half (control) will receive no message. Stimulus content is adapted from materials developed by the Environmental Protection Agency and recently published research.


Risk perception.

Summary of Results

Initial examination of data suggests PSR detected for CHD information but not for lung cancer.