The conception, content validation, and test-retest reliability of the Questionnaire for Screen Time of Adolescents (QueST).

OBJECTIVE: To analyze the content validity and the test-retest reliability of the Questionnaire for Screen Time of Adolescents (QueST). METHODS: A study was conducted with high school adolescents from Southern Brazil enrolled in public education (2019). The QueST measures screen time across five constructs: studying, working/internship-related activities, watching videos, playing games, using social media/chat applications. Content validation involved consulting with experts and adolescents to evaluate whether the five constructs were clear and representing screen time behaviors, all ratings were quantified. The experts' evaluation provided Content Validity Indexes (CVI) for clarity and representativeness of the questionnaire. Students answered the QueST twice (1-week apart), and differences between applications were verified. Test-retest reliability was assessed using Intraclass Correlation Coefficients (ICC) and Bland-Altman analyses. RESULTS: Among the experts, the CVI indicated 94% and 98% of clarity and representativeness, respectively. All items were highly clear for at least 70% of the students. Test-retest reliability was assessed with 104 students (16.3 ±â€¯1.02 years; 66.3% girls). The ICC ranged from 0.41 (95%CI 0.24-0.56) for videos to 0.76 (95%CI 0.66-0.83) for social media/chat applications on weekdays; and from 0.24 (95%CI 0.04-0.41) for videos to 0.67 (95%CI 0.54-0.77) for social media/chat applications on weekends. The lowest mean difference was -4.6 min for working on weekdays, while the highest was 40.6 min for videos on weekends. CONCLUSIONS: The QueST proved to be fair to excellent for measuring different screen time constructs. However, the item of videos (weekends) showed poor stability. The QueST demonstrates satisfactory content validity attested by the experts and adolescents.

Implementation of a school-based physical activity intervention for Brazilian adolescents: a mixed-methods evaluation.

The effectiveness of physical activity interventions can be improved through examining the aspects related to their implementation. However, little such evidence has been collected, particularly in low- and middle-income countries. This study aimed to evaluate the implementation of a school-based physical activity intervention with qualitative and quantitative data from different actors (students, teachers and parents) involved in developing the program. The program was conducted in 2017 with three main components: (i) teacher training, (ii) environmental changes and (iii) educational actions. Mixed-method evaluation was performed by an independent evaluation team using a validated indicator matrix for the implementation process, including the self-reported information of students, teachers and parents, as well as interviews with teachers. In the 3 eligible schools, 350 adolescents (51% girls) answered the implementation questionnaire, as did 45 parents (84% mothers), and 47 teachers (70% female). In the qualitative analysis, 18 teachers participated. Categorical analysis found that the intervention was considered feasible by teachers. In general, teachers had a more positive perception of the implementation than did students. The lack of engagement from the school community and parents and the busy schedule of teachers were indicated to be the main difficulties. In conclusion, despite the teachers' motivation, some barriers prevented the successful implementation of the program.