Volta Elementary: english

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	44,293	2421.5	− 2432	−10.5	× 53 / 231	−2.4
4	44,296	2469.9	− 2473	−3.1	× 59 / 231	−0.8
5	44,297	2492.9	− 2502	−9.1	× 58 / 231	−2.3
6	44,300	2512.4	− 2531	−18.6	× 61 / 231	−4.9
Sum, rounded to a whole point						−10

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	40,994	2442.3	− 2432	10.3	× 62 / 245	2.6
4	40,996	2472.1	− 2473	−0.9	× 66 / 245	−0.2
5	40,997	2505.4	− 2502	3.4	× 57 / 245	0.8
6	41,000	2529.0	− 2531	−2	× 60 / 245	−0.5
Sum, rounded to a whole point						3

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	42,002	2397.8	− 2432	−34.2	× 56 / 243	−7.9
4	42,005	2488.8	− 2473	15.8	× 62 / 243	4
5	42,007	2493.2	− 2502	−8.8	× 64 / 243	−2.3
6	42,009	2525.6	− 2531	−5.4	× 61 / 243	−1.4
Sum, rounded to a whole point						−8

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	42,023	2386.8	− 2432	−45.2	× 61 / 247	−11.2
4	42,026	2453.8	− 2473	−19.2	× 57 / 247	−4.4
5	42,027	2509.3	− 2502	7.3	× 66 / 247	2
6	42,029	2519.7	− 2531	−11.3	× 63 / 247	−2.9
Sum, rounded to a whole point						−17

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	42,161	2406.3	− 2432	−25.7	× 69 / 253	−7
4	42,162	2462.9	− 2473	−10.1	× 59 / 253	−2.4
5	42,163	2521.8	− 2502	19.8	× 59 / 253	4.6
6	42,164	2542.1	− 2531	11.1	× 66 / 253	2.9
Sum, rounded to a whole point						−2

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,930	2389.3	− 2432	−42.7	× 63 / 275	−9.8
4	41,931	2438.7	− 2473	−34.3	× 73 / 275	−9.1
5	41,932	2457.6	− 2502	−44.4	× 71 / 275	−11.5
6	41,933	2514.2	− 2531	−16.8	× 68 / 275	−4.2
Sum, rounded to a whole point						−35

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,955	2360.9	− 2432	−71.1	× 65 / 262	−17.6
4	41,956	2439.1	− 2473	−33.9	× 65 / 262	−8.4
5	41,957	2474.2	− 2502	−27.8	× 65 / 262	−6.9
6	41,958	2458.9	− 2531	−72.1	× 67 / 262	−18.4
Sum, rounded to a whole point						−51

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,786	2398.3	− 2432	−33.7	× 43 / 240	−6
4	41,787	2413.5	− 2473	−59.5	× 67 / 240	−16.6
5	41,788	2468.3	− 2502	−33.7	× 61 / 240	−8.6
6	41,789	2484.7	− 2531	−46.3	× 69 / 240	−13.3
Sum, rounded to a whole point						−45

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,545	2377.2	− 2432	−54.8	× 64 / 240	−14.6
4	41,546	2449.0	− 2473	−24	× 41 / 240	−4.1
5	41,547	2459.7	− 2502	−42.3	× 75 / 240	−13.2
6	41,548	2499.8	− 2531	−31.2	× 60 / 240	−7.8
Sum, rounded to a whole point						−40

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −10, 3, −8, −17, −2, −35, −51, −45, −40 → −22.8
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 13 · 2016→2017: 11 · 2017→2018: 9 · 2018→2019: 15 · 2019→2022: 33 · 2022→2023: 16 · 2023→2024: 6 · 2024→2025: 5 → average 13.5
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 13.5 × 2.66 = 35.9. Upper limit 13.1, lower limit −58.7.

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.