Psychometric properties of brief indexes designed to measure social-cognitive predictors of smoking initiation

The three indexes social influence-norms, social influence-pressure and attitude showed acceptable deviations from the Rasch model, while the two indexes self-efficacy and social influence-behavior were invalidated by negative local dependence. Conclusion: Of the five tested indexes, three (social influence-norms, social influence-pressure and attitude) showed acceptable criterion-related construct validity and may be considered unbiased representations of the theory-based factors if statistical analyses are appropriately adjusted. The results of this population-based study show that the graphical log-linear Rasch model is useful for evaluating health-related behavior indexes and identifying problems, which can be dealt with when using the indexes in future studies.