Submitted to: Public Health Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/5/2006
Publication Date: 11/22/2006
Citation: Baranowski, T., Watson, K., Missaghian, M., Broadfoot, A., Baranowski, J., Cullen, K., Nicklas, T., Fisher, J., O'Donnell, S. 2006. Parent outcome expectancies for purchasing fruit and vegetables: A validation. Public Health Nutrition. 10(3):280-291. Interpretive Summary: Economists report that people tend to behave in ways that maximize their gains and minimize their losses. Gains and losses from doing a behavior have been called "outcome expectancies" in psychology. This study investigated food shoppers' outcome expectancies for purchasing fruit and vegetables, and their comparative outcome expectancies for purchasing fresh versus other fruit and vegetables. Four scales of these outcome expectancies were developed and tested with 161 food shoppers with children (18 years or younger) at home. Traditional and the latest (item response modeling) psychometric techniques were used to assess each scale's validity and reliability. All four scales were demonstrated to have acceptable validity and reliability, and thereby are ready for use in studies of their influence on fruit and vegetable purchases and consumption.
Technical Abstract: Objective: To validate four scales – outcome expectancies for purchasing fruit and for purchasing vegetables, and comparative outcome expectancies for purchasing fresh fruit and for purchasing fresh vegetables versus other forms of fruit and vegetables (F&V). Design: Survey instruments were administered twice, separated by 6 weeks. Setting: Recruited in front of supermarkets and grocery stores; interviews conducted by telephone. Subjects: One hundred sixty-one food shoppers with children (18 years or younger). Results: Single dimension scales were specified for fruit and for vegetable purchasing outcome expectancies, and for comparative (fresh vs. other) fruit and vegetable purchasing outcome expectancies. Item Response Theory parameter estimates revealed easily interpreted patterns in the sequence of items by difficulty of response. Fruit and vegetable purchasing and fresh fruit comparative purchasing outcome expectancy scales were significantly correlated with home F&V availability, after controlling for social desirability of response. Comparative fresh vegetable outcome expectancy scale was significantly bivariately correlated with home vegetable availability, but not after controlling for social desirability. Conclusion: These scales are available to help better understand family F&V purchasing decisions.