because they were not at school or were at school but not in the classroom teaching during lesson time). There is a substantial amount of heterogeneity across rural-urban locations. Rural schools tend to be smaller with, for example, on average 11 teachers as compared to 30 in urban schools, and average class size of 54 versus 77. But even within rural or urban areas there is a large amount of variation: Schools in rural areas range from having 4 to 39 teachers, and class sizes range from 20 to 155 students—corresponding ranges in urban areas are 4 to 50 teachers, and 32 to 193 students.

The ETOS sample of schools was not designed to be representative of those across Tanzania. In particular, while only 17 percent of the ETOS schools are urban, the percentage is 48 in the national sample. Nevertheless, the mean characteristics of the ETOS schools are very similar to those from the national sample, especially after conditioning on urban/rural location. Table 1B reports the same set of characteristics as those in Table 1A but over the full nationally representative sample. Within rural schools, the ETOS schools tend to be slightly smaller and have slightly fewer students overall (they are about 10 percent lower in terms of number of teachers, students, average class size). They also have similar overall teacher absence rates. Within urban areas the characteristics are even more similar, with teacher absence from school being slightly higher in the ETOS sample (18 percent versus 14 percent in the national sample).

# **_3.2 Context for classroom observations_**

In order to describe the general context for this analysis, Table 2 reports summary statistics related to classroom environment and infrastructure in the sample of ETOS schools.<sup>6</sup> While absolute basics such as a readable blackboard and chalk seem to be common in these classrooms, more elaborate features such as functioning electricity is rare, especially in rural areas. Only around a third of classrooms have student work or other charts displayed on the walls. Availability of books for reading is extremely limited as evidenced by the almost complete lack of “corner libraries.”<sup>7</sup> Further to these indicators that describe physical features of the learning environment, Table 3 reports summary statistics on selected teacher practices and behaviors observed. Teachers tend to use textbooks and the blackboard, and generally engage positively with students (e.g. by standing as opposed to sitting, calling on students, or by visiting individual students). But only in about half of the classrooms were students invited to go to the blackboard, or was the teacher observed smiling, laughing, or joking with students. In about one in 5 classrooms, teachers were observed hitting a student. The vast majority of

> 6 These, along with the summary statistics reported in Table 3, are derived from data collected with the SDI instrument administered during the Grade 4 classroom observations. These data are used below to create aggregates that we compare to the other instruments.

> 7 Appendix 1 Table 5 reports the same means, but for the national sample.  The only variable for which there is a substantive difference is the availability of electricity in the classroom: in the national sample only 4 percent of classrooms had electricity while in the ETOS sample 13 percent did.

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