[Methodological aspects of the study on Food Commercialization in Brazilian Schools].

This study presents the methodological aspects of the design and organization of the Food Commercialization in Brazilian Schools study, which aimed to evaluate aspects related to the commercialization of food and beverages in private schools, based on information collected from managers of school cafeterias and street vendors in the immediate vicinity of schools. This is a cross-sectional study of school cafeterias and street vendors near private primary and secondary schools in the 26 Brazilian state capitals. Simple random sampling with inverse replacement was employed; ultimately, 2,241 cafeterias and 699 street vendors were evaluated. The sample loss rate was 21.2%. The questionnaire was developed and evaluated by experts and included questions on nutritional and food information, food infrastructure, convenience, price, availability, variety, and promotion. The logistics involved a coordinating team that conducted training, managed and controlled data quality, local researchers, and a company that assisted in fieldwork. Data collection was conducted from 2022 to 2024. The main implementation challenges were its concurrence with the 2022 electoral period, episodes of violence in schools, internal school policies, the complexity of cultural diversity, and the vast territorial extension of Brazil. Strengths include the novelty of the in-depth and representative data collected, the use of the generated evidence to propose public policies for regulating the school food environment, and the support in building a network of researchers in this area.