The goal of this application is to understand and measure the perceptions that adolescent boys have regarding weight. The proposed studies in this application will document and begin to measure the five constructs of the Integrated Behavior Model, that is, (a) feelings and beliefs about weight including meaning of weight, perception of weight, perception of own weight, accuracy of own perception compared to actual weight, height, and body composition, satisfaction with current weight, height, and body composition, and importance of weight (ATTITUDE);(b) influences others have regarding weight (PERCEIVED NORM);(c) perception of their ability to be in charge of their own weight (PERSONAL AGENCY);(d) intentions to maintain, lose, or gain weight (INTENTIONS);and (e) actions taken to maintain, lose, or gain weight (ACTIONS). The approach will include elicitation, semi-structured interviews with young adolescent boys'ages 11 to 14 that are underweight, about right weight, overweight, obese, and high BMI to generate an item pool from which an instrument, provisionally entitled ADPoSQ (Adolescents'Digital Perception of Self Questionnaire) will be developed. The ADPoSQ will be developed and tested for content validity, internal consistency and test-retest reliability, and factor structure. Boys will create computerized selves (avatars) to describe their current and ideal bodies to augment and expand the survey questions. This instrument eventually will be tested for criterion validity. It will be available to researchers and professionals to screen and target young adolescent boys for appropriate targeted interventions to attain and maintain healthy weight.