Validated scales to assess adult self-efficacy to eat fruits and vegetables.
OBJECTIVE
An audience-centered approach was used to develop valid and reliable scales to measure adult self-efficacy to eat fruit and vegetables.


METHODS
Cross-sectional survey of a national population.


METHODS
New Zealand.


METHODS
A sample of 350 adults ages 25 to 60 years was randomly selected from a nationally representative sampling frame. Overall, 231 questionnaires were returned, producing a 72% response rate. The mean age of subjects was 42.7years; 58% were female; 80% were of European descent; 11% were indigenous Maori.


METHODS
The 76-item, self-administered questionnaire collected data on demographics, fruit and vegetable intakes, stages of change, decisional balance, and self-efficacy (24 items).


METHODS
Principal components analysis with oblimin rotation was performed.


RESULTS
Principal components analysis yielded three distinct and reliable scales for self-efficacy to eat "vegetables," "fruit," and "fruit and vegetables" (Cronbach alpha = .80, .85, and .73, respectively). These scales were correlated, but only the "vegetable" scale was positively correlated with the "fruit and vegetable" scale (Kendall tau r = 0.30, -0.26 [fruit, "fruit and vegetables"], -0.38 [fruit, vegetable]). As predicted, self-efficacy was associated with intake (r = 0.30 [fruit], 0.34 [vegetables]).


CONCLUSIONS
Assuming the factor structure is confirmed in independent samples, these brief psychometrically sound scales may be used to assess adult self-efficacy to eat fruit and to eat vegetables (separately) but not self-efficacy to eat "fruit and vegetables."
Mainvil
Louise A
LA
Department of Human Nutrition, University of Otago, Dunedin, New Zealand. louise.mainvil@otago.ac.nz
Lawson
Rob
R
Horwath
Caroline C
CC
McKenzie
Joanne E
JE
Reeder
Anthony I
AI
D000328:Adult; D000367:Age Factors; D004034:Diet Surveys; D004522:Educational Status; D005163:Factor Analysis, Statistical; D005247:Feeding Behavior / Q000208:ethnology / Q000523:psychology*; D005260:Female; D005518:Food Preferences / Q000208:ethnology / Q000523:psychology*; D005638:Fruit; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D011594:Psychometrics / Q000295:instrumentation*; D020377:Self Efficacy; D012737:Sex Factors; D011795:Surveys and Questionnaires / Q000592:standards*; D014675:Vegetables