Nelson 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	9,911	2416.5	− 2436	−19.5	× 79 / 289	−5.3
4	9,912	2469.1	− 2485	−15.9	× 74 / 289	−4.1
5	9,915	2473.8	− 2528	−54.2	× 64 / 289	−12
6	9,916	2534.5	− 2552	−17.5	× 72 / 289	−4.4
Sum, rounded to a whole point						−26

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	8,963	2435.1	− 2436	−0.9	× 80 / 309	−0.2
4	8,965	2471.4	− 2485	−13.6	× 78 / 309	−3.4
5	8,967	2500.9	− 2528	−27.1	× 81 / 309	−7.1
6	8,969	2551.6	− 2552	−0.4	× 70 / 309	−0.1
Sum, rounded to a whole point						−11

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	9,271	2446.1	− 2436	10.1	× 82 / 324	2.6
4	9,273	2480.2	− 2485	−4.8	× 78 / 324	−1.2
5	9,275	2496.7	− 2528	−31.3	× 77 / 324	−7.4
6	9,276	2528.4	− 2552	−23.6	× 87 / 324	−6.3
Sum, rounded to a whole point						−12

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	9,293	2468.1	− 2436	32.1	× 76 / 331	7.4
4	9,294	2457.4	− 2485	−27.6	× 90 / 331	−7.5
5	9,297	2503.9	− 2528	−24.1	× 82 / 331	−6
6	9,298	2546.7	− 2552	−5.3	× 83 / 331	−1.3
Sum, rounded to a whole point						−7

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	9,369	2465.6	− 2436	29.6	× 62 / 307	6
4	9,370	2485.7	− 2485	0.7	× 75 / 307	0.2
5	9,371	2492.0	− 2528	−36	× 86 / 307	−10.1
6	9,372	2542.7	− 2552	−9.3	× 84 / 307	−2.5
Sum, rounded to a whole point						−6

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	9,338	2417.0	− 2436	−19	× 64 / 254	−4.8
4	9,339	2452.9	− 2485	−32.1	× 70 / 254	−8.8
5	9,340	2482.2	− 2528	−45.8	× 65 / 254	−11.7
6	9,341	2486.2	− 2552	−65.8	× 55 / 254	−14.2
Sum, rounded to a whole point						−40

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	9,314	2423.1	− 2436	−12.9	× 62 / 251	−3.2
4	9,315	2466.7	− 2485	−18.3	× 58 / 251	−4.2
5	9,316	2449.2	− 2528	−78.8	× 67 / 251	−21
6	9,317	2508.0	− 2552	−44	× 64 / 251	−11.2
Sum, rounded to a whole point						−40

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	9,270	2440.9	− 2436	4.9	× 70 / 262	1.3
4	9,271	2489.5	− 2485	4.5	× 56 / 262	1
5	9,272	2472.1	− 2528	−55.9	× 61 / 262	−13
6	9,273	2496.8	− 2552	−55.2	× 75 / 262	−15.8
Sum, rounded to a whole point						−27

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	9,251	2446.5	− 2436	10.5	× 67 / 256	2.7
4	9,252	2466.3	− 2485	−18.7	× 67 / 256	−4.9
5	9,253	2519.7	− 2528	−8.3	× 60 / 256	−1.9
6	9,254	2484.2	− 2552	−67.8	× 62 / 256	−16.4
Sum, rounded to a whole point						−21

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −26, −11, −12, −7, −6, −40, −40, −27, −21 → −21.1
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 15 · 2016→2017: 1 · 2017→2018: 5 · 2018→2019: 1 · 2019→2022: 34 · 2022→2023: 0 · 2023→2024: 13 · 2024→2025: 6 → average 9.4
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 9.4 × 2.66 = 25. Upper limit 3.9, lower limit −46.1.

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.