Table 2:
Count of unique teachers and classrooms, and students per teacher or classroom in analytic sample
| Height | Math | ELA | ||||
|---|---|---|---|---|---|---|
| Grade 4 | Grade 5 | Grade 4 | Grade 5 | Grade 4 | Grade 5 | |
| Unique teachers (N) | 4,263 | 3,687 | 4,721 | 4,249 | 4,366 | 3,978 |
| Mean years observed | 1.90 | 1.98 | 1.88 | 1.94 | 1.82 | 1.87 |
| Students per teacher: | ||||||
| Mean | 36.0 | 39.0 | 38.7 | 42.5 | 35.9 | 39.5 |
| SD | 22.9 | 25.5 | 24.5 | 27.4 | 22.8 | 24.9 |
| p25 | 19 | 20 | 20 | 21 | 19 | 20 |
| p50 | 27 | 29 | 29 | 33 | 26 | 29 |
| p90 | 71 | 76 | 77 | 84 | 72 | 78 |
| Unique classroom-years (N) | 7,594 | 6,848 | 8,712 | 8,138 | 7,941 | 7,451 |
| Students per classroom: | ||||||
| Mean | 20.0 | 20.8 | 20.9 | 22.2 | 19.7 | 21.1 |
| SD | 5.4 | 6.4 | 5.1 | 6.4 | 5.6 | 6.3 |
| p25 | 17 | 17 | 18 | 19 | 16 | 18 |
| p50 | 20 | 21 | 21 | 22 | 20 | 21 |
| p90 | 26 | 28 | 27 | 28 | 26 | 28 |
Notes: Teachers and classrooms are counted only when seven or more students were available with the minimum data to be included in the value-added models for these outcomes. For the full distributions, see the supplemental appendix.