Tehama County Department Of Education: math

The shaded band is this district'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
4	99,071	2417.0	− 2485	−68	× 11 / 79	−9.5
7	99,076	2458.9	− 2567	−108.1	× 19 / 79	−26
8	99,079	2481.2	− 2586	−104.8	× 24 / 79	−31.8
11	99,080	2491.8	− 2628	−136.2	× 25 / 79	−43.1
Sum, rounded to a whole point						−110

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	91,840	2435.9	− 2528	−92.1	× 14 / 90	−14.3
7	91,844	2479.0	− 2567	−88	× 20 / 90	−19.6
8	91,846	2460.0	− 2586	−126	× 27 / 90	−37.8
11	91,848	2473.1	− 2628	−154.9	× 29 / 90	−49.9
Sum, rounded to a whole point						−122

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	94,611	2367.9	− 2436	−68.1	× 16 / 114	−9.6
6	94,617	2488.9	− 2552	−63.1	× 14 / 114	−7.7
7	94,619	2480.7	− 2567	−86.3	× 19 / 114	−14.4
8	94,620	2476.9	− 2586	−109.1	× 35 / 114	−33.5
11	94,622	2497.0	− 2628	−131	× 30 / 114	−34.5
Sum, rounded to a whole point						−100

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
4	94,820	2429.1	− 2485	−55.9	× 14 / 110	−7.1
6	94,824	2481.4	− 2552	−70.6	× 14 / 110	−9
7	94,827	2457.5	− 2567	−109.5	× 24 / 110	−23.9
8	94,828	2453.0	− 2586	−133	× 19 / 110	−23
11	94,831	2484.7	− 2628	−143.3	× 39 / 110	−50.8
Sum, rounded to a whole point						−114

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	95,471	2404.9	− 2528	−123.1	× 15 / 107	−17.3
7	95,473	2482.9	− 2567	−84.1	× 21 / 107	−16.5
8	95,474	2433.6	− 2586	−152.4	× 35 / 107	−49.9
11	95,475	2432.3	− 2628	−195.7	× 36 / 107	−65.8
Sum, rounded to a whole point						−149

2021 from sb_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
7	93,412	2491.5	− 2567	−75.5	× 11 / 11	−75.5
Sum, rounded to a whole point						−76

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
4	95,674	2384.7	− 2485	−100.3	× 12 / 25	−48.1
8	95,678	2463.6	− 2586	−122.4	× 13 / 25	−63.6
Sum, rounded to a whole point						−112

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
8	95,437	2426.2	− 2586	−159.8	× 12 / 12	−159.8
Sum, rounded to a whole point						−160

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
4	95,159	2338.6	− 2485	−146.4	× 13 / 24	−79.3
8	95,163	2431.7	− 2586	−154.3	× 11 / 24	−70.7
Sum, rounded to a whole point						−150

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −110, −122, −100, −114, −149, −76, −112, −160, −150 → −121.4
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 12 · 2016→2017: 22 · 2017→2018: 14 · 2018→2019: 35 · 2019→2021: 73 · 2021→2022: 36 · 2022→2024: 48 · 2024→2025: 10 → average 31.3
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 31.3 × 2.66 = 83.3. Upper limit −38.1, lower limit −204.7.

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 — for a district, the total across its schools. From 2014–15, 2015–16, 2016–17, 2017–18, 2018–19, 2020–21, 2021–22, 2022–23, 2023–24, 2024–25, 2025–26.