Oak Park Independent: 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
7	104,852	2522.5	− 2567	−44.5	× 15 / 57	−11.7
8	104,855	2510.2	− 2586	−75.8	× 21 / 57	−27.9
11	104,856	2562.8	− 2628	−65.2	× 21 / 57	−24
Sum, rounded to a whole point						−64

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
7	97,394	2564.5	− 2567	−2.5	× 11 / 66	−0.4
8	97,395	2575.3	− 2586	−10.7	× 27 / 66	−4.4
11	97,397	2592.5	− 2628	−35.5	× 28 / 66	−15.1
Sum, rounded to a whole point						−20

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	100,216	2542.2	− 2552	−9.8	× 11 / 55	−2
7	100,218	2540.2	− 2567	−26.8	× 12 / 55	−5.8
8	100,221	2539.2	− 2586	−46.8	× 17 / 55	−14.5
11	100,222	2592.8	− 2628	−35.2	× 15 / 55	−9.6
Sum, rounded to a whole point						−32

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
7	100,373	2596.2	− 2567	29.2	× 13 / 63	6
8	100,376	2577.3	− 2586	−8.7	× 19 / 63	−2.6
11	100,377	2605.7	− 2628	−22.3	× 31 / 63	−11
Sum, rounded to a whole point						−8

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
8	101,039	2597.7	− 2586	11.7	× 14 / 40	4.1
11	101,040	2590.2	− 2628	−37.8	× 26 / 40	−24.6
Sum, rounded to a whole point						−20

2021 from sb_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
7	98,897	2626.0	− 2567	59	× 11 / 23	28.2
11	98,899	2628.8	− 2628	0.8	× 12 / 23	0.4
Sum, rounded to a whole point						29

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
7	101,287	2558.8	− 2567	−8.2	× 11 / 24	−3.8
8	101,288	2603.3	− 2586	17.3	× 13 / 24	9.4
Sum, rounded to a whole point						6

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
7	101,121	2614.8	− 2567	47.8	× 12 / 39	14.7
8	101,122	2558.5	− 2586	−27.5	× 11 / 39	−7.8
11	101,123	2597.6	− 2628	−30.4	× 16 / 39	−12.5
Sum, rounded to a whole point						−6

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
11	100,664	2603.1	− 2628	−24.9	× 15 / 15	−24.9
Sum, rounded to a whole point						−25

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −64, −20, −32, −8, −20, 29, 6, −6, −25 → −15.6
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 44 · 2016→2017: 12 · 2017→2018: 24 · 2018→2019: 12 · 2019→2021: 49 · 2021→2022: 23 · 2022→2023: 12 · 2023→2025: 19 → average 24.4
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 24.4 × 2.66 = 64.9. Upper limit 49.3, lower limit −80.5.

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.