Twin Hills Charter Middle: 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
6	95,702	2533.5	− 2552	−18.5	× 112 / 333	−6.2
7	95,705	2536.1	− 2567	−30.9	× 114 / 333	−10.6
8	95,707	2582.2	− 2586	−3.8	× 107 / 333	−1.2
Sum, rounded to a whole point						−18

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	88,811	2522.3	− 2552	−29.7	× 96 / 309	−9.2
7	88,814	2561.0	− 2567	−6	× 115 / 309	−2.2
8	88,815	2545.0	− 2586	−41	× 98 / 309	−13
Sum, rounded to a whole point						−24

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	91,369	2542.1	− 2552	−9.9	× 88 / 304	−2.9
7	91,371	2558.5	− 2567	−8.5	× 100 / 304	−2.8
8	91,373	2582.7	− 2586	−3.3	× 116 / 304	−1.3
Sum, rounded to a whole point						−7

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	91,562	2528.2	− 2552	−23.8	× 83 / 257	−7.7
7	91,563	2564.6	− 2567	−2.4	× 94 / 257	−0.9
8	91,566	2592.3	− 2586	6.3	× 80 / 257	2
Sum, rounded to a whole point						−7

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	92,205	2542.6	− 2552	−9.4	× 78 / 263	−2.8
7	92,206	2556.5	− 2567	−10.5	× 93 / 263	−3.7
8	92,207	2602.1	− 2586	16.1	× 92 / 263	5.6
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
6	92,455	2519.8	− 2552	−32.2	× 63 / 204	−9.9
7	92,456	2596.3	− 2567	29.3	× 76 / 204	10.9
8	92,457	2570.8	− 2586	−15.2	× 65 / 204	−4.8
Sum, rounded to a whole point						−4

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	92,363	2540.3	− 2552	−11.7	× 53 / 195	−3.2
7	92,364	2563.1	− 2567	−3.9	× 70 / 195	−1.4
8	92,365	2626.1	− 2586	40.1	× 72 / 195	14.8
Sum, rounded to a whole point						10

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	92,260	2551.7	− 2552	−0.3	× 68 / 203	−0.1
7	92,261	2571.3	− 2567	4.3	× 65 / 203	1.4
8	92,262	2599.6	− 2586	13.6	× 70 / 203	4.7
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
6	91,978	2528.5	− 2552	−23.5	× 60 / 203	−6.9
7	91,979	2591.2	− 2567	24.2	× 82 / 203	9.8
8	91,980	2610.8	− 2586	24.8	× 61 / 203	7.5
Sum, rounded to a whole point						10

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −18, −24, −7, −7, −1, −4, 10, 6, 10 → −3.9
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 6 · 2016→2017: 17 · 2017→2018: 0 · 2018→2019: 6 · 2019→2022: 3 · 2022→2023: 14 · 2023→2024: 4 · 2024→2025: 4 → average 6.8
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 6.8 × 2.66 = 18.1. Upper limit 14.2, lower limit −22.

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.