Willowbrook Middle: 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
6	39,191	2421.4	− 2552	−130.6	× 96 / 360	−34.8
7	39,193	2418.9	− 2567	−148.1	× 130 / 360	−53.5
8	39,195	2429.9	− 2586	−156.1	× 134 / 360	−58.1
Sum, rounded to a whole point						−146

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	36,382	2421.2	− 2552	−130.8	× 61 / 279	−28.6
7	36,385	2434.7	− 2567	−132.3	× 91 / 279	−43.2
8	36,386	2440.3	− 2586	−145.7	× 127 / 279	−66.3
Sum, rounded to a whole point						−138

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	37,146	2416.8	− 2552	−135.2	× 68 / 229	−40.1
7	37,148	2434.3	− 2567	−132.7	× 71 / 229	−41.1
8	37,151	2434.0	− 2586	−152	× 90 / 229	−59.7
Sum, rounded to a whole point						−141

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	37,096	2419.2	− 2552	−132.8	× 66 / 234	−37.5
7	37,098	2439.3	− 2567	−127.7	× 84 / 234	−45.8
8	37,100	2428.7	− 2586	−157.3	× 84 / 234	−56.5
Sum, rounded to a whole point						−140

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	37,299	2547.0	− 2552	−5	× 63 / 168	−1.9
7	37,300	2445.9	− 2567	−121.1	× 50 / 168	−36
8	37,301	2491.9	− 2586	−94.1	× 55 / 168	−30.8
Sum, rounded to a whole point						−69

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	37,218	2568.1	− 2552	16.1	× 78 / 269	4.7
7	37,219	2529.7	− 2567	−37.3	× 94 / 269	−13
8	37,220	2535.7	− 2586	−50.3	× 97 / 269	−18.1
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
6	37,251	2590.6	− 2552	38.6	× 94 / 283	12.8
7	37,252	2582.1	− 2567	15.1	× 97 / 283	5.2
8	37,253	2547.2	− 2586	−38.8	× 92 / 283	−12.6
Sum, rounded to a whole point						5

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	37,101	2576.6	− 2552	24.6	× 97 / 295	8.1
7	37,102	2588.8	− 2567	21.8	× 105 / 295	7.8
8	37,103	2613.3	− 2586	27.3	× 93 / 295	8.6
Sum, rounded to a whole point						24

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
6	36,938	2595.1	− 2552	43.1	× 97 / 302	13.8
7	36,939	2602.4	− 2567	35.4	× 103 / 302	12.1
8	36,940	2623.7	− 2586	37.7	× 102 / 302	12.7
Sum, rounded to a whole point						39

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −146, −138, −141, −140, −69, −27, 5, 24, 39 → −65.9
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 8 · 2016→2017: 3 · 2017→2018: 1 · 2018→2019: 71 · 2019→2022: 42 · 2022→2023: 32 · 2023→2024: 19 · 2024→2025: 15 → average 23.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 23.9 × 2.66 = 63.6. Upper limit −2.3, lower limit −129.5.

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.