that of most public industrial and agricultural investments. Other research interprets beneficial findings with caution.<sup>7</sup> It is inherently difficult to explain investment in public pre-primary. Investing requires revenue, which is less abundant in poor areas. However, poor areas may have higher net benefits from public pre-primary, making them more likely to invest. This may explain why economic development is not a good predictor of pre-primary enrollment. Many European countries have among the highest public preschool enrollment rates, but Brazil, Ecuador, Mexico, and Thailand have higher rates than either the U.S. or the U.K. (UNESCO 2006).<sup>8</sup> Formal, school-based pre-primary education in Brazil has expanded rapidly but unevenly in recent years. Figure 1 shows the national enrollment rate during 1995-2008.<sup>9</sup> Enrollment expanded from 8% to 18% among 0-3 year-olds (cr`eche age) and from 48% to 80% among 4-6 year-olds (preschool age). The Figure 2 maps show 2008 state-level averages. In 2008, cr`eche enrollment ranged from 6% to 32%, and preschool enrollment ranged from 57% to 91%.<sup>10</sup> Private pre-primary education in Brazil is of higher quality than public pre-primary. Table 1 presents 2008 means of several school-level variables including pre-primary students per teacher, the fraction of pre-primary teachers with at least some post-secondary education,<sup>11</sup> and the fraction of pre-primary schools with a designated school building,<sup>12</sup> electricity, an indoor bathroom, a library, and a computer. Private pre-primary schools outperform public on each measure of quality, and the difference is statistically significant at the 0.01 level. Some of the differences are large. Public institutions have 3 more children per teacher, and 15% fewer teachers with post-secondary training, than private institutions. Indoor bathrooms are present in 80% of

> 7Anderson (2008) notes that some of the most influential randomized evaluations carried out in the U.S.— the Abecedarian Project, the Perry Preschool Program, and the Early Training Project—have serious statistical inference problems and confounds. DHHS (2010) finds that advantages gained during a year of the Head Start preschool program at age four dissipated by 2nd grade. Gormley _et al._ (2010) find that pre-K quality is key.

> 8There is also substantial within-country variation. For example, in the U.S., while Florida, Georgia, and Oklahoma provide free preschool to all four year-olds, 12 states do not fund any pre-primary (Pre-K Now 2010).

> 9In 2007, school became mandatory for six year olds, when primary education expanded from an eight to a nine year sequence. This explains the sharp spike in the ages 4-6 graph in 2007, as parents of six-year-olds no longer had the option to keep their children out of formal schooling.

> 10Averages are based on parental self reports in the National Household Sample Survey (PNAD). For a detailed discussion of heterogenous trends in access to pre-primary in Brazil during 1996-2008, see Evans and Kosec (2010).

> 11This includes any post-high school education, whether or not a degree was obtained.

> 12Some schools report using a teacher’s house, church, community center, local business, barn, or shed.

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