Attitude and perceived behavioral control.

The instrument consists of 71 items with Likert scale response option , of frequency and agree and disagree options. The scale measures the factors: behavioral beliefs, value attributed to these beliefs, normative beliefs, willingness to conform to normative expectations, descriptive norm, opportunity of use and behavioral control itself

The test shows a high reliability with Cronbach's alpha of 0.9154 for the global scale. As for the factors is reported: behavioral beliefs (0.91), value attributed to these beliefs (0.79), normative beliefs (0.64), willingness to conform to normative expectations (0.85), descriptive norm (0.62), user opportunity (0.81) and behavioral control itself (0.94).

Self-administered

The variable attitude is obtained from the sum of the product of scores of behavioral beliefs by the scores of the attributed value to each of these beliefs ; the scores of subjective norm are the result of the sum of product of the scores of normative beliefs by the willingness to comply with these beliefs and finally the rating of perceived behavioral control is obtained from the sum of the product of the scores of behavioral control itself and of exposure to use opportunities. Subsequently, the ratings on these variables are divided by the number of items corresponding to each variable to obtain scales from 5 to 25 points

Rodríguez-Kuri, S. E., Diaz-Negrete, D. B., Gracia-Gutiérrez de Velasco, S. E., Guerrero-Huesca, J. A., & Gómez-Maqueo, E. L. (2007). Capacidad predictiva de la teoría de la conducta planificada en la intención y uso de drogas ilícitas entre estudiantes mexicanos. Salud Mental, 30(1), 68-81.