Reliability and validity of nutrition knowledge questionnaire for adults.

OBJECTIVE To determine the validity and reliability of a nutrition knowledge questionnaire for adults in California. METHODS A convenience sample of adults was recruited for cognitive interviews. A mail-based survey of 400 randomly selected addresses was used to assess internal consistency (Cronbach α). Researchers assessed content validity (Student t test) and test-retest reliability (Pearson correlation) in a convenience sample of university students who had previously taken a college nutrition course, compared with students who had not. RESULTS Twenty adults participated in cognitive interviews, 94 adults returned the mailed questionnaire, and 48 university students participated in validity and reliability testing. Cronbach α = .91 and test-retest r = 0.95, demonstrating internal consistency reliability and test-retest reliability. Students who had taken a college-level nutrition course scored significantly higher compared with students who had not (P < .001), demonstrating construct validity. CONCLUSIONS AND IMPLICATIONS Findings show that the questionnaire is a valid and reliable nutrition knowledge measure for use in California and may be of use in other places.