We use a linear probability model to uncover whether some observed characteristics at the municipal level help explain the 13 municipalities’ self-selection. We regress a dummy variable that takes the value of 1 if the municipality _m_ extended the winter break of municipal schools in 2009 and 0 otherwise on a vector of pre-determined covariates: the municipality GDP per capita in 2007, the municipality population size in 2007, the number of confirmed cases of H1N1 per 100,000 inhabitants (until July 25, 2009), and municipal averages of students’, teachers’ and principals’ characteristics. (Table A.2).<sup>6</sup> Although several coefficients are statistically significant, most are very small. The adjusted R<sup>2</sup> suggests that the municipalities’ observed characteristics do not explain much of the local authority’s decision to follow the state guidelines.

# **3 Data**

The Brazilian public education system is decentralized. The 26 states, the Federal district, and the 5,570 municipalities share the responsibilities of provisioning education. According to the Brazilian Constitution of 1988, the municipal governments should prioritize early childhood, primary (grades 1 to 5), and lower secondary education (grades 6 to 9), and the state authorities should prioritize primary, lower secondary, and upper secondary education (grades 10 to 12). Hence, the schools located in all the Brazilian municipalities can be managed either by the state government or by the municipal government. We will refer to the first group of schools as statemanaged and the second group of schools as locally-managed. In each of the 645 municipalities in São Paulo state, there is at least one locally-managed school and one state-managed school offering either preschool, primary, lower, or upper secondary education.

> 6All the descriptive statistics presented are relative to 2007 and based on the Brazilian Ministry of Education questionnaires that students, teachers, and principals fill out. Tables are available in the online appendix. The principal managerial skills is an index ranging from 0 to 1. It is calculated based on teachers’ answers of how frequently they believe that the principal pays attention to students’ learning, administrative norms, and school maintenance; motivates the teachers and encourages new ideas, and takes into consideration teachers’ inputs; and whether teachers trust the principal and can participate in decisions related to their work. All these variables have four possible answers: never (value 0), sometimes (0.33), often (0.66), and always (1). The principal managerial skills index at the teacher level is an average of these answers, and the index at the school level is an average of teachers’ answers. The student motivation index is similarly defined. It is calculated based on the teachers’ answers on whether students’ learning deficit is caused by low student motivation or bad behavior in the classroom. These variables have two possible answers: yes (0) and no (1). The index includes the variable ’students’ absenteeism’ which can take three possible values: a moderate/big issue (0), a small issue (0.5), and not a problem (1). The student motivation index is an average of these answers. Finally, the teacher motivation index also ranges from 0 to 1, and it is calculated based on students’ answers of how frequently the teacher corrects their reading and math homework. The variable has three possible answers: always (1), sometimes (0.5), and never (0). The teacher motivation at the school level averages students’ answers.

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