Culverdale Elementary: math

The shaded band is this school's normal range. If nothing about how it works changes, nearly every future year should land inside it. Zero means the typical student just meets the state standard. The small numbers under the years are how many students were tested.

Step 1 · Each year's result

For each grade tested, take the average (mean) scale score from the California Department of Education's results file, and subtract the lowest score that counts as "Standard Met" for that grade. That is the grade's distance from standard. Weight each grade by its share of the students tested, then add the grades up. Grades where the state hides the average because ten or fewer students tested are left out entirely.

2015 from sb_ca2015_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	53,108	2458.4	− 2436	22.4	× 96 / 471	4.6
4	53,110	2467.2	− 2485	−17.8	× 103 / 471	−3.9
5	53,112	2505.2	− 2528	−22.8	× 141 / 471	−6.8
6	53,114	2535.7	− 2552	−16.3	× 131 / 471	−4.5
Sum, rounded to a whole point						−11

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	49,348	2447.3	− 2436	11.3	× 88 / 431	2.3
4	49,349	2501.5	− 2485	16.5	× 82 / 431	3.1
5	49,352	2498.0	− 2528	−30	× 105 / 431	−7.3
6	49,353	2549.9	− 2552	−2.1	× 156 / 431	−0.8
Sum, rounded to a whole point						−3

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	50,711	2439.2	− 2436	3.2	× 111 / 437	0.8
4	50,714	2451.2	− 2485	−33.8	× 104 / 437	−8
5	50,715	2513.3	− 2528	−14.7	× 89 / 437	−3
6	50,718	2536.0	− 2552	−16	× 133 / 437	−4.9
Sum, rounded to a whole point						−15

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	50,747	2459.4	− 2436	23.4	× 105 / 410	6
4	50,749	2489.6	− 2485	4.6	× 94 / 410	1.1
5	50,751	2490.4	− 2528	−37.6	× 99 / 410	−9.1
6	50,753	2538.0	− 2552	−14	× 112 / 410	−3.8
Sum, rounded to a whole point						−6

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	50,955	2449.7	− 2436	13.7	× 97 / 418	3.2
4	50,956	2504.7	− 2485	19.7	× 115 / 418	5.4
5	50,957	2511.7	− 2528	−16.3	× 104 / 418	−4.1
6	50,958	2528.6	− 2552	−23.4	× 102 / 418	−5.7
Sum, rounded to a whole point						−1

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	50,881	2426.4	− 2436	−9.6	× 93 / 365	−2.4
4	50,882	2482.8	− 2485	−2.2	× 87 / 365	−0.5
5	50,883	2484.9	− 2528	−43.1	× 93 / 365	−11
6	50,884	2549.4	− 2552	−2.6	× 92 / 365	−0.7
Sum, rounded to a whole point						−15

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	50,847	2442.2	− 2436	6.2	× 76 / 360	1.3
4	50,848	2482.9	− 2485	−2.1	× 102 / 360	−0.6
5	50,849	2516.3	− 2528	−11.7	× 80 / 360	−2.6
6	50,850	2575.6	− 2552	23.6	× 102 / 360	6.7
Sum, rounded to a whole point						5

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	50,708	2450.5	− 2436	14.5	× 80 / 339	3.4
4	50,709	2483.7	− 2485	−1.3	× 81 / 339	−0.3
5	50,710	2505.2	− 2528	−22.8	× 89 / 339	−6
6	50,711	2584.0	− 2552	32	× 89 / 339	8.4
Sum, rounded to a whole point						6

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	50,470	2457.4	− 2436	21.4	× 79 / 318	5.3
4	50,471	2476.2	− 2485	−8.8	× 72 / 318	−2
5	50,472	2525.6	− 2528	−2.4	× 82 / 318	−0.6
6	50,473	2558.5	− 2552	6.5	× 85 / 318	1.7
Sum, rounded to a whole point						4

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −11, −3, −15, −6, −1, −15, 5, 6, 4 → −4
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 8 · 2016→2017: 12 · 2017→2018: 9 · 2018→2019: 5 · 2019→2022: 14 · 2022→2023: 20 · 2023→2024: 1 · 2024→2025: 2 → average 8.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 8.9 × 2.66 = 23.7. Upper limit 19.7, lower limit −27.7.

Why 2.66? It is the standard factor from quality control, the work of Walter Shewhart and W. Edwards Deming. It turns "how much the result typically changes in a year" into "how far it can wander by chance alone".

Years with no result (no state tests were given in spring 2020) are skipped: the year-to-year change runs from the last year with a result to the next one.

Step 3 · Free or reduced-price meals

The share of enrolled students eligible for free or reduced-price meals. From 2014–15, 2015–16, 2016–17, 2017–18, 2018–19, 2020–21, 2021–22, 2022–23, 2023–24, 2024–25, 2025–26.