John H. Still: 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	61,878	2339.4	− 2436	−96.6	× 101 / 621	−15.7
4	61,880	2416.5	− 2485	−68.5	× 83 / 621	−9.2
5	61,882	2400.3	− 2528	−127.7	× 97 / 621	−19.9
6	61,884	2433.8	− 2552	−118.2	× 85 / 621	−16.2
7	61,886	2457.7	− 2567	−109.3	× 127 / 621	−22.4
8	61,888	2465.1	− 2586	−120.9	× 128 / 621	−24.9
Sum, rounded to a whole point						−108

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	57,439	2363.5	− 2436	−72.5	× 99 / 585	−12.3
4	57,441	2422.0	− 2485	−63	× 90 / 585	−9.7
5	57,443	2419.7	− 2528	−108.3	× 76 / 585	−14.1
6	57,445	2449.7	− 2552	−102.3	× 88 / 585	−15.4
7	57,447	2464.3	− 2567	−102.7	× 123 / 585	−21.6
8	57,450	2499.4	− 2586	−86.6	× 109 / 585	−16.1
Sum, rounded to a whole point						−89

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	59,115	2350.0	− 2436	−86	× 92 / 625	−12.7
4	59,116	2396.3	− 2485	−88.7	× 91 / 625	−12.9
5	59,119	2401.8	− 2528	−126.2	× 95 / 625	−19.2
6	59,121	2447.4	− 2552	−104.6	× 81 / 625	−13.6
7	59,123	2440.7	− 2567	−126.3	× 142 / 625	−28.7
8	59,125	2481.6	− 2586	−104.4	× 124 / 625	−20.7
Sum, rounded to a whole point						−108

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	59,229	2370.6	− 2436	−65.4	× 102 / 653	−10.2
4	59,231	2378.7	− 2485	−106.3	× 96 / 653	−15.6
5	59,233	2407.6	− 2528	−120.4	× 94 / 653	−17.3
6	59,235	2450.6	− 2552	−101.4	× 97 / 653	−15.1
7	59,237	2464.6	− 2567	−102.4	× 128 / 653	−20.1
8	59,239	2471.4	− 2586	−114.6	× 136 / 653	−23.9
Sum, rounded to a whole point						−102

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	59,487	2377.2	− 2436	−58.8	× 94 / 638	−8.7
4	59,488	2417.7	− 2485	−67.3	× 101 / 638	−10.7
5	59,489	2429.5	− 2528	−98.5	× 88 / 638	−13.6
6	59,490	2426.6	− 2552	−125.4	× 93 / 638	−18.3
7	59,491	2468.1	− 2567	−98.9	× 140 / 638	−21.7
8	59,492	2468.3	− 2586	−117.7	× 122 / 638	−22.5
Sum, rounded to a whole point						−95

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	59,570	2382.6	− 2436	−53.4	× 77 / 556	−7.4
4	59,571	2408.1	− 2485	−76.9	× 70 / 556	−9.7
5	59,572	2425.6	− 2528	−102.4	× 94 / 556	−17.3
6	59,573	2448.7	− 2552	−103.3	× 92 / 556	−17.1
7	59,574	2449.3	− 2567	−117.7	× 123 / 556	−26
8	59,575	2449.5	− 2586	−136.5	× 100 / 556	−24.6
Sum, rounded to a whole point						−102

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	59,528	2387.6	− 2436	−48.4	× 62 / 575	−5.2
4	59,529	2417.9	− 2485	−67.1	× 83 / 575	−9.7
5	59,530	2416.5	− 2528	−111.5	× 65 / 575	−12.6
6	59,531	2450.3	− 2552	−101.7	× 95 / 575	−16.8
7	59,532	2459.4	− 2567	−107.6	× 148 / 575	−27.7
8	59,533	2444.0	− 2586	−142	× 122 / 575	−30.1
Sum, rounded to a whole point						−102

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	59,459	2361.2	− 2436	−74.8	× 58 / 554	−7.8
4	59,460	2430.1	− 2485	−54.9	× 64 / 554	−6.3
5	59,461	2427.0	− 2528	−101	× 84 / 554	−15.3
6	59,462	2479.1	− 2552	−72.9	× 62 / 554	−8.2
7	59,463	2473.4	− 2567	−93.6	× 137 / 554	−23.1
8	59,464	2461.6	− 2586	−124.4	× 149 / 554	−33.5
Sum, rounded to a whole point						−94

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	59,216	2397.7	− 2436	−38.3	× 48 / 474	−3.9
4	59,217	2408.8	− 2485	−76.2	× 57 / 474	−9.2
5	59,218	2440.1	− 2528	−87.9	× 56 / 474	−10.4
6	59,219	2440.2	− 2552	−111.8	× 78 / 474	−18.4
7	59,220	2466.7	− 2567	−100.3	× 103 / 474	−21.8
8	59,221	2472.4	− 2586	−113.6	× 132 / 474	−31.6
Sum, rounded to a whole point						−95

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −108, −89, −108, −102, −95, −102, −102, −94, −95 → −99.4
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 19 · 2016→2017: 19 · 2017→2018: 6 · 2018→2019: 7 · 2019→2022: 7 · 2022→2023: 0 · 2023→2024: 8 · 2024→2025: 1 → average 8.4
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 8.4 × 2.66 = 22.3. Upper limit −77.1, lower limit −121.7.

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.