Related Experiment Video
Updated: Jun 8, 2026

Breakfast Habits among Schoolchildren in the City of Uruguaiana, Brazil
Published on: July 29, 2020
Reliability of a questionnaire on substance use among adolescent students, Brazil
Adelmo de Souza Machado Neto1, Tarcisio Matos Andrade, Gilênio Borges Fernandes
1Departamento de Medicina, Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Salvador, BA, Brasil. machadonetoa@yahoo.com.br
Objective:
To analyze reliability of a self-applied questionnaire on substance use and misuse among adolescent students.
Methods:
Two cross-sectional studies were carried out for the instrument test-retest. The sample comprised male and female students aged 1119 years from public and private schools (elementary, middle, and high school students) in the city of Salvador, Northeastern Brazil, in 2006. A total of 591 questionnaires were applied in the test and 467 in the retest. Descriptive statistics, the Kappa index, Cronbach's alpha and intraclass correlation were estimated.
Results:
The prevalence of substance use/misuse was similar in both test and retest. Sociodemographic variables showed a "moderate" to "almost perfect" agreement for the Kappa index, and a "satisfactory" (>0.75) consistency for Cronbach's alpha and intraclass correlation. The age which psychoactive substances (tobacco, alcohol, and cannabis) were first used and chronological age were similar in both studies. Test-retest reliability was found to be a good indicator of students' age of initiation and their patterns of substance use.
Conclusions:
The questionnaire reliability was found to be satisfactory in the population studied.
Related Concept Videos
Reliability and Validity
Surveys
Substance Use Disorders Affecting Sleep
Understanding the concepts of physical dependence,...
Self-Report Tests of Personality
Cross-Sectional Research
Bioavailability Study Design: Healthy Subjects Versus Patients