Validity and reliability of a dietary stages of change measure among economically disadvantaged African-American adolescents.

Purpose: To examine the construct validity and 2-month test-retest reliability of a staging measure for assessing readiness to consume five or more daily servings of fruits and vegetables among economically disadvantaged African-American adolescents.

Design: Longitudinal survey.

Setting: Youth services agencies serving low-income communities in New York, New Jersey, and Pennsylvania.

Subjects: African-American adolescents (N  =  390) aged 11 to 14 years.

Measures: Self-report measures of stage of change and fruit and vegetable consumption.

Analysis: Correlation analysis and analysis of covariance were used to examine, cross-sectionally, whether fruit and vegetable consumption differed by stage of change (validity assessment). Correlation analysis and Cohen's kappa (κ) were used to assess the degree of association and level of agreement between stages longitudinally (test-retest reliability assessment).

Results: Fruit and vegetable consumption was moderately correlated with stage of change (r ≥ .54, p  =  .000). Consistent with the transtheoretical model, youths' consumption increased from earlier to later stages (p  =  .000). Forty-six percent of youths were in the same stage at both measurements. The correlation between stages was .26, and Cohen's κ was .20 (p  =  .000).

Conclusions: Despite preliminary evidence of construct validity, the low test-retest reliability found suggests that further research and testing are needed to improve the stability of the measure.