Ina Arbuckle 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	56,747	2369.7	− 2436	−66.3	× 91 / 319	−18.9
4	56,749	2414.0	− 2485	−71	× 86 / 319	−19.1
5	56,750	2444.6	− 2528	−83.4	× 65 / 319	−17
6	56,753	2493.7	− 2552	−58.3	× 77 / 319	−14.1
Sum, rounded to a whole point						−69

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	52,690	2397.3	− 2436	−38.7	× 75 / 303	−9.6
4	52,692	2418.8	− 2485	−66.2	× 76 / 303	−16.6
5	52,694	2438.1	− 2528	−89.9	× 83 / 303	−24.6
6	52,695	2459.2	− 2552	−92.8	× 69 / 303	−21.1
Sum, rounded to a whole point						−72

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	54,208	2371.2	− 2436	−64.8	× 73 / 304	−15.6
4	54,211	2419.1	− 2485	−65.9	× 74 / 304	−16
5	54,212	2429.4	− 2528	−98.6	× 75 / 304	−24.3
6	54,214	2461.2	− 2552	−90.8	× 82 / 304	−24.5
Sum, rounded to a whole point						−80

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	54,322	2389.5	− 2436	−46.5	× 80 / 304	−12.2
4	54,324	2405.2	− 2485	−79.8	× 73 / 304	−19.2
5	54,326	2444.5	− 2528	−83.5	× 75 / 304	−20.6
6	54,328	2446.2	− 2552	−105.8	× 76 / 304	−26.5
Sum, rounded to a whole point						−78

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	54,563	2381.5	− 2436	−54.5	× 73 / 298	−13.4
4	54,564	2415.0	− 2485	−70	× 75 / 298	−17.6
5	54,565	2442.0	− 2528	−86	× 73 / 298	−21.1
6	54,566	2461.2	− 2552	−90.8	× 77 / 298	−23.5
Sum, rounded to a whole point						−75

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	54,601	2357.0	− 2436	−79	× 68 / 259	−20.7
4	54,602	2384.1	− 2485	−100.9	× 61 / 259	−23.8
5	54,603	2394.6	− 2528	−133.4	× 63 / 259	−32.4
6	54,604	2422.3	− 2552	−129.7	× 67 / 259	−33.6
Sum, rounded to a whole point						−111

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	54,552	2370.9	− 2436	−65.1	× 44 / 229	−12.5
4	54,553	2393.8	− 2485	−91.2	× 66 / 229	−26.3
5	54,554	2420.1	− 2528	−107.9	× 57 / 229	−26.9
6	54,555	2402.7	− 2552	−149.3	× 62 / 229	−40.4
Sum, rounded to a whole point						−106

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	54,422	2366.7	− 2436	−69.3	× 65 / 237	−19
4	54,423	2426.3	− 2485	−58.7	× 46 / 237	−11.4
5	54,424	2417.1	− 2528	−110.9	× 70 / 237	−32.8
6	54,425	2414.4	− 2552	−137.6	× 56 / 237	−32.5
Sum, rounded to a whole point						−96

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	54,162	2347.9	− 2436	−88.1	× 59 / 240	−21.7
4	54,163	2401.1	− 2485	−83.9	× 69 / 240	−24.1
5	54,164	2434.4	− 2528	−93.6	× 44 / 240	−17.2
6	54,165	2413.3	− 2552	−138.7	× 68 / 240	−39.3
Sum, rounded to a whole point						−102

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −69, −72, −80, −78, −75, −111, −106, −96, −102 → −87.7
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 3 · 2016→2017: 8 · 2017→2018: 2 · 2018→2019: 3 · 2019→2022: 36 · 2022→2023: 5 · 2023→2024: 10 · 2024→2025: 6 → average 9.1
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 9.1 × 2.66 = 24.2. Upper limit −63.5, lower limit −111.9.

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.