Scales of smoking-related self-efficacy, beliefs, and intention: assessing measurement invariance among intermittent and daily high school smokers.

Purpose: To examine the factorial validity and measurement invariance of scales that measure smoking-related self-efficacy, beliefs, and intention between daily and intermittent adolescent smokers.
Design: Cross-sectional survey design.
Setting: Selected high schools in eastern Texas.
Subjects: Subjects were 2888 high school current smokers; mean age 16.2 years; 53.5% male; 67.4% White, 17.8% Hispanic, 6.2% Black, 8.6% "other." Daily smokers comprised 37.9% of the sample (i.e., smoked at least one cigarette every day 30 days prior to the survey).
Measures: Smoking-related self-efficacy and intention were measured by three items; beliefs were measured by four items.
Analysis: Confirmatory factor analyses were conducted to test the invariance of the measures between daily and intermittent smokers. Fit indices included comparative fit index (CFI), nonnormed fix index (NNFI), and root mean square error of approximation (RMSEA).
Results: The three-factor measurement model had good fit for daily (CFI = .97, NNFI = .95, RMSEA = .09) and intermittent (CFI = .96, NNFI = .95, RMSEA = .09) smokers. Evidence of strong factorial invariance was found for the factors between the smoking subgroups (CFI = .96, NNFI = .96, RMSEA = .08).
Conclusion: These measures may be used to capture and compare scores on self-efficacy to resist smoking, beliefs about benefits of smoking, and intention to smoke between daily and intermittent adolescent smokers.