Clarence Ruth 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	85,081	2384.7	− 2436	−51.3	× 97 / 359	−13.9
4	85,084	2424.0	− 2485	−61	× 86 / 359	−14.6
5	85,085	2449.3	− 2528	−78.7	× 89 / 359	−19.5
6	85,088	2469.7	− 2552	−82.3	× 87 / 359	−19.9
Sum, rounded to a whole point						−68

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,909	2384.0	− 2436	−52	× 76 / 334	−11.8
4	78,911	2424.3	− 2485	−60.7	× 93 / 334	−16.9
5	78,913	2434.9	− 2528	−93.1	× 79 / 334	−22
6	78,915	2469.4	− 2552	−82.6	× 86 / 334	−21.3
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	81,065	2393.6	− 2436	−42.4	× 83 / 333	−10.6
4	81,067	2405.6	− 2485	−79.4	× 78 / 333	−18.6
5	81,070	2421.8	− 2528	−106.2	× 94 / 333	−30
6	81,071	2480.4	− 2552	−71.6	× 78 / 333	−16.8
Sum, rounded to a whole point						−76

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	81,215	2379.5	− 2436	−56.5	× 85 / 331	−14.5
4	81,216	2419.2	− 2485	−65.8	× 78 / 331	−15.5
5	81,219	2423.1	− 2528	−104.9	× 76 / 331	−24.1
6	81,220	2476.1	− 2552	−75.9	× 92 / 331	−21.1
Sum, rounded to a whole point						−75

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	81,748	2405.5	− 2436	−30.5	× 72 / 304	−7.2
4	81,749	2427.6	− 2485	−57.4	× 81 / 304	−15.3
5	81,750	2438.0	− 2528	−90	× 76 / 304	−22.5
6	81,751	2445.2	− 2552	−106.8	× 75 / 304	−26.3
Sum, rounded to a whole point						−71

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	81,969	2382.1	− 2436	−53.9	× 68 / 251	−14.6
4	81,970	2420.3	− 2485	−64.7	× 59 / 251	−15.2
5	81,971	2415.5	− 2528	−112.5	× 71 / 251	−31.8
6	81,972	2466.7	− 2552	−85.3	× 53 / 251	−18
Sum, rounded to a whole point						−80

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	81,929	2372.9	− 2436	−63.1	× 60 / 255	−14.8
4	81,930	2388.3	− 2485	−96.7	× 69 / 255	−26.2
5	81,931	2408.8	− 2528	−119.2	× 58 / 255	−27.1
6	81,932	2426.2	− 2552	−125.8	× 68 / 255	−33.5
Sum, rounded to a whole point						−102

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	81,941	2360.1	− 2436	−75.9	× 70 / 265	−20
4	81,942	2400.3	− 2485	−84.7	× 63 / 265	−20.1
5	81,943	2408.4	− 2528	−119.6	× 74 / 265	−33.4
6	81,944	2479.4	− 2552	−72.6	× 58 / 265	−15.9
Sum, rounded to a whole point						−89

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	81,613	2375.9	− 2436	−60.1	× 70 / 273	−15.4
4	81,614	2367.7	− 2485	−117.3	× 65 / 273	−27.9
5	81,615	2387.5	− 2528	−140.5	× 64 / 273	−32.9
6	81,616	2449.1	− 2552	−102.9	× 74 / 273	−27.9
Sum, rounded to a whole point						−104

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −68, −72, −76, −75, −71, −80, −102, −89, −104 → −81.9
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 4 · 2016→2017: 4 · 2017→2018: 1 · 2018→2019: 4 · 2019→2022: 9 · 2022→2023: 22 · 2023→2024: 13 · 2024→2025: 15 → average 9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 9 × 2.66 = 23.9. Upper limit −58, lower limit −105.8.

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.