Shaffer 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	19,951	2389.0	− 2436	−47	× 24 / 133	−8.5
4	19,954	2454.1	− 2485	−30.9	× 21 / 133	−4.9
5	19,955	2494.0	− 2528	−34	× 23 / 133	−5.9
6	19,958	2468.1	− 2552	−83.9	× 16 / 133	−10.1
7	19,959	2515.8	− 2567	−51.2	× 25 / 133	−9.6
8	19,961	2549.5	− 2586	−36.5	× 24 / 133	−6.6
Sum, rounded to a whole point						−46

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	18,929	2398.7	− 2436	−37.3	× 20 / 126	−5.9
4	18,931	2464.3	− 2485	−20.7	× 27 / 126	−4.4
5	18,934	2457.5	− 2528	−70.5	× 20 / 126	−11.2
6	18,936	2517.6	− 2552	−34.4	× 22 / 126	−6
7	18,937	2524.7	− 2567	−42.3	× 12 / 126	−4
8	18,940	2544.3	− 2586	−41.7	× 25 / 126	−8.3
Sum, rounded to a whole point						−40

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	19,261	2383.1	− 2436	−52.9	× 19 / 116	−8.7
4	19,263	2462.9	− 2485	−22.1	× 19 / 116	−3.6
5	19,265	2449.6	− 2528	−78.4	× 25 / 116	−16.9
6	19,267	2479.2	− 2552	−72.8	× 22 / 116	−13.8
7	19,269	2540.0	− 2567	−27	× 18 / 116	−4.2
8	19,270	2552.8	− 2586	−33.2	× 13 / 116	−3.7
Sum, rounded to a whole point						−51

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	19,262	2417.9	− 2436	−18.1	× 21 / 117	−3.2
4	19,265	2484.0	− 2485	−1	× 19 / 117	−0.2
5	19,266	2452.6	− 2528	−75.4	× 19 / 117	−12.2
6	19,269	2514.2	− 2552	−37.8	× 22 / 117	−7.1
7	19,270	2535.9	− 2567	−31.1	× 20 / 117	−5.3
8	19,273	2575.1	− 2586	−10.9	× 16 / 117	−1.5
Sum, rounded to a whole point						−30

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	19,410	2385.2	− 2436	−50.8	× 23 / 138	−8.5
4	19,411	2469.0	− 2485	−16	× 23 / 138	−2.7
5	19,412	2475.2	− 2528	−52.8	× 21 / 138	−8
6	19,413	2496.1	− 2552	−55.9	× 23 / 138	−9.3
7	19,414	2561.4	− 2567	−5.6	× 25 / 138	−1
8	19,415	2565.0	− 2586	−21	× 23 / 138	−3.5
Sum, rounded to a whole point						−33

2021 from sb_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	18,907	2344.4	− 2436	−91.6	× 20 / 120	−15.3
4	18,908	2463.6	− 2485	−21.4	× 18 / 120	−3.2
5	18,909	2439.4	− 2528	−88.6	× 23 / 120	−17
6	18,910	2466.8	− 2552	−85.2	× 18 / 120	−12.8
7	18,911	2536.6	− 2567	−30.4	× 21 / 120	−5.3
8	18,912	2578.6	− 2586	−7.4	× 20 / 120	−1.2
Sum, rounded to a whole point						−55

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	19,441	2361.0	− 2436	−75	× 27 / 126	−16.1
4	19,442	2440.7	− 2485	−44.3	× 21 / 126	−7.4
5	19,443	2424.4	− 2528	−103.6	× 18 / 126	−14.8
6	19,444	2470.9	− 2552	−81.1	× 24 / 126	−15.4
7	19,445	2519.1	− 2567	−47.9	× 16 / 126	−6.1
8	19,446	2587.6	− 2586	1.6	× 20 / 126	0.3
Sum, rounded to a whole point						−60

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	19,388	2384.1	− 2436	−51.9	× 23 / 143	−8.3
4	19,389	2409.5	− 2485	−75.5	× 26 / 143	−13.7
5	19,390	2436.0	− 2528	−92	× 23 / 143	−14.8
6	19,391	2478.4	− 2552	−73.6	× 21 / 143	−10.8
7	19,392	2508.1	− 2567	−58.9	× 32 / 143	−13.2
8	19,393	2531.1	− 2586	−54.9	× 18 / 143	−6.9
Sum, rounded to a whole point						−68

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	19,328	2415.6	− 2436	−20.4	× 28 / 157	−3.6
4	19,329	2436.6	− 2485	−48.4	× 24 / 157	−7.4
5	19,330	2451.8	− 2528	−76.2	× 24 / 157	−11.6
6	19,331	2476.7	− 2552	−75.3	× 23 / 157	−11
7	19,332	2501.8	− 2567	−65.2	× 23 / 157	−9.6
8	19,333	2506.3	− 2586	−79.7	× 35 / 157	−17.8
Sum, rounded to a whole point						−61

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	19,289	2389.8	− 2436	−46.2	× 33 / 149	−10.2
4	19,290	2456.2	− 2485	−28.8	× 28 / 149	−5.4
5	19,291	2440.9	− 2528	−87.1	× 27 / 149	−15.8
6	19,292	2476.6	− 2552	−75.4	× 20 / 149	−10.1
7	19,293	2517.9	− 2567	−49.1	× 23 / 149	−7.6
8	19,294	2532.7	− 2586	−53.3	× 18 / 149	−6.4
Sum, rounded to a whole point						−56

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −46, −40, −51, −30, −33, −55, −60, −68, −61, −56 → −50
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 6 · 2016→2017: 11 · 2017→2018: 21 · 2018→2019: 3 · 2019→2021: 22 · 2021→2022: 5 · 2022→2023: 8 · 2023→2024: 7 · 2024→2025: 5 → average 9.8
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 9.8 × 2.66 = 26.1. Upper limit −23.9, lower limit −76.1.

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.