James Foster 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	37,406	2447.8	− 2436	11.8	× 86 / 355	2.9
4	37,408	2463.8	− 2485	−21.2	× 93 / 355	−5.6
5	37,410	2495.1	− 2528	−32.9	× 81 / 355	−7.5
6	37,412	2512.7	− 2552	−39.3	× 95 / 355	−10.5
Sum, rounded to a whole point						−21

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	34,802	2465.2	− 2436	29.2	× 78 / 335	6.8
4	34,804	2505.4	− 2485	20.4	× 90 / 335	5.5
5	34,807	2507.2	− 2528	−20.8	× 89 / 335	−5.5
6	34,808	2556.8	− 2552	4.8	× 78 / 335	1.1
Sum, rounded to a whole point						8

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	35,448	2443.9	− 2436	7.9	× 69 / 336	1.6
4	35,451	2508.6	− 2485	23.6	× 83 / 336	5.8
5	35,452	2499.5	− 2528	−28.5	× 91 / 336	−7.7
6	35,455	2516.1	− 2552	−35.9	× 93 / 336	−9.9
Sum, rounded to a whole point						−10

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	35,459	2461.4	− 2436	25.4	× 65 / 305	5.4
4	35,460	2492.2	− 2485	7.2	× 65 / 305	1.5
5	35,463	2494.5	− 2528	−33.5	× 82 / 305	−9
6	35,464	2547.2	− 2552	−4.8	× 93 / 305	−1.5
Sum, rounded to a whole point						−4

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	35,626	2445.3	− 2436	9.3	× 109 / 332	3.1
4	35,627	2480.4	− 2485	−4.6	× 70 / 332	−1
5	35,628	2505.2	− 2528	−22.8	× 69 / 332	−4.7
6	35,629	2533.3	− 2552	−18.7	× 84 / 332	−4.7
Sum, rounded to a whole point						−7

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	35,515	2426.8	− 2436	−9.2	× 71 / 290	−2.3
4	35,516	2509.8	− 2485	24.8	× 73 / 290	6.2
5	35,517	2509.9	− 2528	−18.1	× 51 / 290	−3.2
6	35,518	2540.2	− 2552	−11.8	× 95 / 290	−3.9
Sum, rounded to a whole point						−3

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	35,520	2450.7	− 2436	14.7	× 76 / 289	3.9
4	35,521	2495.4	− 2485	10.4	× 76 / 289	2.7
5	35,522	2518.3	− 2528	−9.7	× 79 / 289	−2.7
6	35,523	2527.0	− 2552	−25	× 58 / 289	−5
Sum, rounded to a whole point						−1

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	35,382	2462.8	− 2436	26.8	× 57 / 293	5.2
4	35,383	2506.8	− 2485	21.8	× 79 / 293	5.9
5	35,384	2489.9	− 2528	−38.1	× 76 / 293	−9.9
6	35,385	2562.8	− 2552	10.8	× 81 / 293	3
Sum, rounded to a whole point						4

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	35,223	2457.2	− 2436	21.2	× 75 / 312	5.1
4	35,224	2544.4	− 2485	59.4	× 62 / 312	11.8
5	35,225	2498.1	− 2528	−29.9	× 91 / 312	−8.7
6	35,226	2549.9	− 2552	−2.1	× 84 / 312	−0.6
Sum, rounded to a whole point						8

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −21, 8, −10, −4, −7, −3, −1, 4, 8 → −2.9
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 29 · 2016→2017: 18 · 2017→2018: 6 · 2018→2019: 3 · 2019→2022: 4 · 2022→2023: 2 · 2023→2024: 5 · 2024→2025: 4 → average 8.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 8.9 × 2.66 = 23.7. Upper limit 20.8, lower limit −26.6.

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.