Parent outcome expectancies for purchasing fruit and vegetables: a validation

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 and 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.