were at or above 4 in Emotional Support and a little higher for Classroom Organization—with Instructional Support lagging well behind (around 2).

The Teach-derived measures of Share of Time Teaching (84 percent) and Share of Time Teaching and Learning (81 percent) are close to that from SDI for the former, and higher than those for SDI and Stallings for the latter. This suggests that _Teach_ “penalizes” teachers less than SDI and Stallings for students being off-task. The area-level scores suggest that these teachers score relatively highly on Classroom Culture (3.65 on the 5-point scale), average on Instruction (2.43), and relatively poorly on Socioemotional Skills (2.07). Again, this overall pattern is not unusual. For example, in primary schools in Pakistan, Molina et al (2018) find similar absolute scores (3.9, 2.3, 2.0 respectively), and a similar pattern in the Mindanao province of the Philippines (Molina et al. 2018b). The results are very close to those from the administration of _Teach_ to Grade 3 teachers in a nationally representative sample of Tanzanian schools in 2019 as a part of the RISE research program (3.3, 2.6, and 2.0 respectively).

The various instruments differ in their identification of variation in the sample. Figure 1 shows the coefficients of variation (CV; the standard deviation divided by the mean) for the Level 1 variables for each of the instruments. Because it normalizes the variation of a variable in the data by its mean, the CV allows one to compare variability in a unit-free way.<sup>25</sup> For most of the variables in SDI, Stallings, and CLASS, CVs are similar and lie between 0.2 and 0.35. Comparing across tools, three findings stand out. First, _Teach_ tends to identify less variation in the data on Share of Time Teaching or Share of Time Teaching and Learning than either SDI or Stallings. Second, the CVs for the SDI and Stallings measure of Classroom Environment are very high. Third, the CVs for the CLASS measure of Classroom Organization and the _Teach_ measure of Classroom Culture stand out as being particularly low.

In Round 1, in addition to teachers from Grade 4, teachers from Grades 3 and 5 were observed using the SDI and Stallings instruments. Figure 2 illustrates how the variation across all schools (as measured by the standard deviation of the grade 4 value of the variable) compares to the variation across grades within schools (as measured by the mean, across schools, of the within-school standard deviation of each variable across grades 3, 4, and, 5). These show that while the variation across schools is always larger than that within schools, the latter is nevertheless substantial. Across these variables, the average within-school standard deviation is only 40 percent less than the across-school standard deviation (with a range from 38

> 25 Note, however, that the CV is only thought to be a good measure for variables that are on a ratio scale (i.e. that have a meaningful 0).  Most of the variables here are not on such a scale—we nevertheless use the CV to illustrate how the empirically measured variability across indicators measured by their standard deviation, scaled by their means, varies within and across the observation systems.

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