Isleton Elementary: 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	61,115	2439.5	− 2436	3.5	× 23 / 97	0.8
4	61,117	2442.7	− 2485	−42.3	× 20 / 97	−8.7
5	61,119	2493.1	− 2528	−34.9	× 24 / 97	−8.6
6	61,121	2498.8	− 2552	−53.2	× 30 / 97	−16.5
Sum, rounded to a whole point						−33

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	56,699	2419.3	− 2436	−16.7	× 24 / 89	−4.5
4	56,702	2497.4	− 2485	12.4	× 25 / 89	3.5
5	56,703	2530.7	− 2528	2.7	× 21 / 89	0.6
6	56,705	2497.2	− 2552	−54.8	× 19 / 89	−11.7
Sum, rounded to a whole point						−12

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,349	2453.7	− 2436	17.7	× 15 / 91	2.9
4	58,350	2461.7	− 2485	−23.3	× 27 / 91	−6.9
5	58,352	2571.5	− 2528	43.5	× 27 / 91	12.9
6	58,355	2529.2	− 2552	−22.8	× 22 / 91	−5.5
Sum, rounded to a whole point						3

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,477	2419.4	− 2436	−16.6	× 16 / 92	−2.9
4	58,480	2462.0	− 2485	−23	× 22 / 92	−5.5
5	58,481	2553.8	− 2528	25.8	× 25 / 92	7
6	58,484	2591.2	− 2552	39.2	× 29 / 92	12.4
Sum, rounded to a whole point						11

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,723	2436.4	− 2436	0.4	× 20 / 90	0.1
4	58,724	2490.1	− 2485	5.1	× 22 / 90	1.2
5	58,725	2543.4	− 2528	15.4	× 18 / 90	3.1
6	58,726	2562.1	− 2552	10.1	× 30 / 90	3.4
Sum, rounded to a whole point						8

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,798	2384.8	− 2436	−51.2	× 23 / 93	−12.7
4	58,799	2445.5	− 2485	−39.5	× 23 / 93	−9.8
5	58,800	2563.3	− 2528	35.3	× 24 / 93	9.1
6	58,801	2495.4	− 2552	−56.6	× 23 / 93	−14
Sum, rounded to a whole point						−27

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,752	2430.2	− 2436	−5.8	× 22 / 101	−1.3
4	58,753	2411.9	− 2485	−73.1	× 27 / 101	−19.5
5	58,754	2531.6	− 2528	3.6	× 26 / 101	0.9
6	58,755	2550.5	− 2552	−1.5	× 26 / 101	−0.4
Sum, rounded to a whole point						−20

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,669	2453.4	− 2436	17.4	× 22 / 100	3.8
4	58,670	2477.5	− 2485	−7.5	× 22 / 100	−1.7
5	58,671	2499.5	− 2528	−28.5	× 30 / 100	−8.6
6	58,672	2533.4	− 2552	−18.6	× 26 / 100	−4.8
Sum, rounded to a whole point						−11

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,426	2459.6	− 2436	23.6	× 23 / 96	5.7
4	58,427	2500.7	− 2485	15.7	× 20 / 96	3.3
5	58,428	2569.8	− 2528	41.8	× 23 / 96	10
6	58,429	2490.0	− 2552	−62	× 30 / 96	−19.4
Sum, rounded to a whole point						0

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −33, −12, 3, 11, 8, −27, −20, −11, 0 → −9
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 21 · 2016→2017: 15 · 2017→2018: 8 · 2018→2019: 3 · 2019→2022: 35 · 2022→2023: 7 · 2023→2024: 9 · 2024→2025: 11 → average 13.6
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 13.6 × 2.66 = 36.2. Upper limit 27.2, lower limit −45.2.

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.