Bell Middle: math · Schoolio

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	74,803	2465.6	− 2552	−86.4	× 285 / 855	−28.8
7	74,805	2469.4	− 2567	−97.6	× 275 / 855	−31.4
8	74,807	2499.9	− 2586	−86.1	× 295 / 855	−29.7
Sum, rounded to a whole point						−90

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	69,505	2459.0	− 2552	−93	× 262 / 849	−28.7
7	69,507	2486.9	− 2567	−80.1	× 297 / 849	−28
8	69,508	2490.1	− 2586	−95.9	× 290 / 849	−32.8
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
6	71,337	2471.7	− 2552	−80.3	× 233 / 755	−24.8
7	71,339	2490.3	− 2567	−76.7	× 233 / 755	−23.7
8	71,342	2450.1	− 2586	−135.9	× 289 / 755	−52
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
6	71,483	2492.3	− 2552	−59.7	× 226 / 679	−19.9
7	71,484	2500.2	− 2567	−66.8	× 219 / 679	−21.5
8	71,487	2504.0	− 2586	−82	× 234 / 679	−28.3
Sum, rounded to a whole point						−70

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	71,968	2468.1	− 2552	−83.9	× 234 / 677	−29
7	71,969	2497.8	− 2567	−69.2	× 228 / 677	−23.3
8	71,970	2498.6	− 2586	−87.4	× 215 / 677	−27.8
Sum, rounded to a whole point						−80

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	72,058	2438.0	− 2552	−114	× 235 / 681	−39.3
7	72,059	2466.9	− 2567	−100.1	× 236 / 681	−34.7
8	72,060	2467.8	− 2586	−118.2	× 210 / 681	−36.4
Sum, rounded to a whole point						−110

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	72,052	2458.7	− 2552	−93.3	× 215 / 693	−28.9
7	72,053	2450.3	− 2567	−116.7	× 243 / 693	−40.9
8	72,054	2474.4	− 2586	−111.6	× 235 / 693	−37.8
Sum, rounded to a whole point						−108

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	72,034	2423.2	− 2552	−128.8	× 198 / 673	−37.9
7	72,035	2481.0	− 2567	−86	× 232 / 673	−29.6
8	72,036	2470.0	− 2586	−116	× 243 / 673	−41.9
Sum, rounded to a whole point						−109

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	71,750	2437.8	− 2552	−114.2	× 226 / 652	−39.6
7	71,751	2462.2	− 2567	−104.8	× 200 / 652	−32.1
8	71,752	2491.6	− 2586	−94.4	× 226 / 652	−32.7
Sum, rounded to a whole point						−104

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −90, −89, −100, −70, −80, −110, −108, −109, −104 → −95.6
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 1 · 2016→2017: 11 · 2017→2018: 30 · 2018→2019: 10 · 2019→2022: 30 · 2022→2023: 2 · 2023→2024: 1 · 2024→2025: 5 → average 11.3
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 11.3 × 2.66 = 30.1. Upper limit −65.5, lower limit −125.7.

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.