the median value of the 2010 age-grade distortion in high FE in Rio de Janeiro, which means that we cut our sample in half to consider only the schools that had low distortion prior to 2011.<sup>19</sup> The results presented in Tables 13 and 14 indicate very positive effects for the certified CMS schools on IDEB and IDERio results, respectively. Even after including all controls, Carioca Middle Schools had an increase of 0.806 standard deviations in IDEB results (column (2) of Table 13) and of 0.681 standard deviations on IDERio results (column (2) of Table 14). Columns (3) show a smaller but still significant and positive results for the CMS when we restrict our sample to schools that eventually became Single-Shift. Columns (4) also show positive and significant when we restrict our sample to low age-grade distortion schools. Single-Shift non-CMS schools, on the other hand, have a non-significant impact on IDEB results. Columns (3) and (4) of Tables 13 and 14 show even negative results for these non-certified Single-Shift middle schools.<sup>20</sup> Table 15 then analyzes the components of IDEB middle school results. Columns (1), (3) and (5) show the results with school and year fixed-effects, and controlling for whether the schools participated in “Schools of Tomorrow” and “More Education” programs in the years when they were part of these programs. Columns (2), (4) and (6) show the results including all controls. The results for Carioca Middle Schools indicate that the observed increase in IDEB comes from an increase in both student performance and approval rates. No results in Table 15 were statistically significant for the Single-Shift non-certified middle schools.

Table 16 presents the results for model (2) in Single-Shift middle schools (including CMS and non-CMS Single-Shift middle schools), with IDEB as the outcome variable. Columns (1) and (2) of Table 16 show the results of Single-Shift middle schools that entered the program in 2011 and that entered the program in 2012 and 2013 controlling for school and year fixed effects and other controls that vary over time. The coefficients of Table 16 indicate that not only the schools that entered the program earlier but also those schools that entered the program in 2012 and 2013 had positive increases in IDEB. As shown in column (2), in the model including all controls, the schools that entered the program in the first year had an increase of 0.566 standard deviation in IDEB results. The schools that entered the program later had a similar increase in standard deviations.

Columns (3) and (4) show the results considering the restricted samples. The results of column (3) – which restricts the sample to only schools that eventually entered the program until 2015 – are not statistically significant, which is probably due to the fact that only 7 new middle schools entered the Single-Shift program in 2014 or 2015 and they were all non-certified middle schools. Note that the schools that entered the program in 2014/2015 are the control group in column (3). When we restrict the sample to schools with low age-grade distortion, as presented in column (4) of Table 16, the results are positive and significant, either for those that entered the program in 2011 as for those that entered in 2012 or 2013. These results are interesting in telling us that not only the pilot CMS (Carioca “Experimental” Middle Schools) observed positive results, the expansion of the policy was also very successful in increasing IDEB results.

> 19 We also estimated – as an additional robustness check – a model considering as treatment only the Single-Shift middle schools (certified and non-certified) with a low decrease in age-grade distortion. The Single-Shift schools with an increase higher than 10 percentage points in age-grade distortion were considered as control group. Ten percentage points represents the median decrease of age-grade distortion in the treatment schools. We find similar results, with positive and significant (slightly smaller) coefficients for CMSs and non-significant results for non-certified SingleShift middle schools.

> 20 Column (3) of Table 13 presents the estimated effect of -0.300 standard deviation (statistically significant at 1%) and column (4) presents the estimated effect of -0.340 standard deviation (statistically significant at 10%). The other coefficients for the non-certified Single-Shift middle schools are not significantly different from zero.

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