Yuba: science · Schoolio

The shaded band is this county'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.

2019 from cast_ca2019_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	28,518	198.2	− 214	−15.8	× 1111 / 3632	−4.8
8	28,519	396.5	− 415	−18.5	× 1114 / 3632	−5.7
11	28,520	597.3	− 615	−17.7	× 854 / 3632	−4.2
12	28,521	597.3	− 615	−17.7	× 553 / 3632	−2.7
Sum, rounded to a whole point						−17

2021 from cast_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	30,339	188.2	− 214	−25.8	× 733 / 2170	−8.7
8	30,340	390.8	− 415	−24.2	× 631 / 2170	−7
11	30,341	594.9	− 615	−20.1	× 281 / 2170	−2.6
12	30,342	599.9	− 615	−15.1	× 525 / 2170	−3.7
Sum, rounded to a whole point						−22

2022 from cast_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	35,344	198.7	− 214	−15.3	× 1142 / 3534	−4.9
8	35,345	395.8	− 415	−19.2	× 1022 / 3534	−5.6
11	35,346	595.3	− 615	−19.7	× 865 / 3534	−4.8
12	35,347	597.3	− 615	−17.7	× 505 / 3534	−2.5
Sum, rounded to a whole point						−18

2023 from cast_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	35,287	198.2	− 214	−15.8	× 1217 / 3147	−6.1
8	35,288	393.9	− 415	−21.1	× 1041 / 3147	−7
11	35,289	602.9	− 615	−12.1	× 813 / 3147	−3.1
12	35,290	593.9	− 615	−21.1	× 76 / 3147	−0.5
Sum, rounded to a whole point						−17

2024 from cast_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	35,334	197.5	− 214	−16.5	× 1159 / 3226	−5.9
8	35,335	396.2	− 415	−18.8	× 1142 / 3226	−6.7
11	35,337	599.4	− 615	−15.6	× 857 / 3226	−4.1
12	35,338	587.3	− 615	−27.7	× 68 / 3226	−0.6
Sum, rounded to a whole point						−17

2025 from cast_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	35,337	197.3	− 214	−16.7	× 1198 / 3297	−6.1
8	35,338	397.9	− 415	−17.1	× 1194 / 3297	−6.2
11	35,340	602.1	− 615	−12.9	× 842 / 3297	−3.3
12	35,341	593.4	− 615	−21.6	× 63 / 3297	−0.4
Sum, rounded to a whole point						−16

2026 from cast_ca2026_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
5	35,115	197.8	− 214	−16.2	× 1191 / 3263	−5.9
8	35,116	397.3	− 415	−17.7	× 1199 / 3263	−6.5
11	35,117	603.8	− 615	−11.2	× 791 / 3263	−2.7
12	35,118	593.2	− 615	−21.8	× 82 / 3263	−0.5
Sum, rounded to a whole point						−16

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −17, −22, −18, −17, −17, −16, −16 → −17.6
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2019→2021: 5 · 2021→2022: 4 · 2022→2023: 1 · 2023→2024: 0 · 2024→2025: 1 · 2025→2026: 0 → average 1.8
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 1.8 × 2.66 = 4.8. Upper limit −12.8, lower limit −22.4.

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 county, 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.