Walnut Grove 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	97,370	2391.4	− 2436	−44.6	× 82 / 450	−8.1
4	97,372	2428.8	− 2485	−56.2	× 77 / 450	−9.6
5	97,375	2418.1	− 2528	−109.9	× 94 / 450	−23
6	97,376	2443.6	− 2552	−108.4	× 70 / 450	−16.9
7	97,379	2490.5	− 2567	−76.5	× 63 / 450	−10.7
8	97,380	2462.3	− 2586	−123.7	× 64 / 450	−17.6
Sum, rounded to a whole point						−86

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	90,274	2383.0	− 2436	−53	× 82 / 486	−8.9
4	90,276	2430.8	− 2485	−54.2	× 91 / 486	−10.1
5	90,278	2436.4	− 2528	−91.6	× 80 / 486	−15.1
6	90,281	2443.0	− 2552	−109	× 104 / 486	−23.3
7	90,282	2478.3	− 2567	−88.7	× 71 / 486	−13
8	90,284	2465.7	− 2586	−120.3	× 58 / 486	−14.4
Sum, rounded to a whole point						−85

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	92,917	2388.1	− 2436	−47.9	× 80 / 524	−7.3
4	92,918	2418.5	− 2485	−66.5	× 92 / 524	−11.7
5	92,921	2447.1	− 2528	−80.9	× 95 / 524	−14.7
6	92,922	2468.0	− 2552	−84	× 91 / 524	−14.6
7	92,924	2455.0	− 2567	−112	× 98 / 524	−20.9
8	92,926	2478.1	− 2586	−107.9	× 68 / 524	−14
Sum, rounded to a whole point						−83

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	93,116	2400.9	− 2436	−35.1	× 74 / 538	−4.8
4	93,117	2422.0	− 2485	−63	× 84 / 538	−9.8
5	93,120	2457.9	− 2528	−70.1	× 92 / 538	−12
6	93,121	2469.0	− 2552	−83	× 104 / 538	−16
7	93,124	2461.9	− 2567	−105.1	× 90 / 538	−17.6
8	93,125	2461.3	− 2586	−124.7	× 94 / 538	−21.8
Sum, rounded to a whole point						−82

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	93,773	2405.5	− 2436	−30.5	× 76 / 513	−4.5
4	93,774	2444.6	− 2485	−40.4	× 73 / 513	−5.7
5	93,775	2459.2	− 2528	−68.8	× 81 / 513	−10.9
6	93,776	2444.4	− 2552	−107.6	× 95 / 513	−19.9
7	93,777	2463.0	− 2567	−104	× 101 / 513	−20.5
8	93,778	2475.6	− 2586	−110.4	× 87 / 513	−18.7
Sum, rounded to a whole point						−80

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	94,004	2401.8	− 2436	−34.2	× 80 / 311	−8.8
4	94,005	2414.9	− 2485	−70.1	× 74 / 311	−16.7
5	94,006	2422.6	− 2528	−105.4	× 74 / 311	−25.1
6	94,007	2452.9	− 2552	−99.1	× 83 / 311	−26.4
Sum, rounded to a whole point						−77

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	93,912	2400.7	− 2436	−35.3	× 71 / 316	−7.9
4	93,913	2413.5	− 2485	−71.5	× 92 / 316	−20.8
5	93,914	2409.6	− 2528	−118.4	× 74 / 316	−27.7
6	93,915	2449.9	− 2552	−102.1	× 79 / 316	−25.5
Sum, rounded to a whole point						−82

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	93,793	2383.6	− 2436	−52.4	× 93 / 381	−12.8
4	93,794	2400.9	− 2485	−84.1	× 107 / 381	−23.6
5	93,795	2422.5	− 2528	−105.5	× 103 / 381	−28.5
6	93,796	2445.5	− 2552	−106.5	× 78 / 381	−21.8
Sum, rounded to a whole point						−87

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	93,525	2386.2	− 2436	−49.8	× 95 / 408	−11.6
4	93,526	2413.8	− 2485	−71.2	× 99 / 408	−17.3
5	93,527	2433.8	− 2528	−94.2	× 106 / 408	−24.5
6	93,528	2432.8	− 2552	−119.2	× 108 / 408	−31.6
Sum, rounded to a whole point						−85

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −86, −85, −83, −82, −80, −77, −82, −87, −85 → −83
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 1 · 2016→2017: 2 · 2017→2018: 1 · 2018→2019: 2 · 2019→2022: 3 · 2022→2023: 5 · 2023→2024: 5 · 2024→2025: 2 → average 2.6
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 2.6 × 2.66 = 6.9. Upper limit −76.1, lower limit −89.9.

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.