Potter Valley Community Unified: math

The shaded band is this district'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	43,654	2398.9	− 2436	−37.1	× 18 / 58	−11.5
4	43,655	2440.2	− 2485	−44.8	× 17 / 58	−13.1
5	43,658	2478.8	− 2528	−49.2	× 12 / 58	−10.2
6	43,659	2466.4	− 2552	−85.6	× 11 / 58	−16.2
Sum, rounded to a whole point						−51

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	40,356	2429.7	− 2436	−6.3	× 23 / 128	−1.1
4	40,358	2436.3	− 2485	−48.7	× 20 / 128	−7.6
5	40,359	2488.5	− 2528	−39.5	× 22 / 128	−6.8
6	40,361	2463.6	− 2552	−88.4	× 16 / 128	−11.1
7	40,364	2430.8	− 2567	−136.2	× 14 / 128	−14.9
8	40,365	2433.9	− 2586	−152.1	× 16 / 128	−19
11	40,368	2509.9	− 2628	−118.1	× 17 / 128	−15.7
Sum, rounded to a whole point						−76

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,367	2400.9	− 2436	−35.1	× 20 / 131	−5.4
4	41,369	2432.4	− 2485	−52.6	× 26 / 131	−10.4
5	41,371	2474.2	− 2528	−53.8	× 20 / 131	−8.2
6	41,372	2506.9	− 2552	−45.1	× 20 / 131	−6.9
7	41,374	2442.1	− 2567	−124.9	× 16 / 131	−15.3
8	41,376	2438.4	− 2586	−147.6	× 14 / 131	−15.8
11	41,379	2534.8	− 2628	−93.2	× 15 / 131	−10.7
Sum, rounded to a whole point						−73

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,396	2432.0	− 2436	−4	× 24 / 138	−0.7
4	41,397	2446.4	− 2485	−38.6	× 25 / 138	−7
5	41,400	2497.5	− 2528	−30.5	× 24 / 138	−5.3
6	41,401	2438.8	− 2552	−113.2	× 19 / 138	−15.6
7	41,404	2482.1	− 2567	−84.9	× 18 / 138	−11.1
8	41,405	2448.6	− 2586	−137.4	× 14 / 138	−13.9
11	41,408	2542.1	− 2628	−85.9	× 14 / 138	−8.7
Sum, rounded to a whole point						−62

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,543	2404.6	− 2436	−31.4	× 24 / 157	−4.8
4	41,544	2488.5	− 2485	3.5	× 27 / 157	0.6
5	41,545	2504.8	− 2528	−23.2	× 20 / 157	−3
6	41,546	2493.9	− 2552	−58.1	× 28 / 157	−10.4
7	41,547	2471.3	− 2567	−95.7	× 17 / 157	−10.4
8	41,548	2494.2	− 2586	−91.8	× 20 / 157	−11.7
11	41,549	2474.5	− 2628	−153.5	× 21 / 157	−20.5
Sum, rounded to a whole point						−60

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,300	2424.8	− 2436	−11.2	× 19 / 148	−1.4
4	41,301	2430.9	− 2485	−54.1	× 20 / 148	−7.3
5	41,302	2515.3	− 2528	−12.7	× 17 / 148	−1.5
6	41,303	2506.7	− 2552	−45.3	× 21 / 148	−6.4
7	41,304	2514.6	− 2567	−52.4	× 29 / 148	−10.3
8	41,305	2446.6	− 2586	−139.4	× 21 / 148	−19.8
11	41,306	2520.0	− 2628	−108	× 21 / 148	−15.3
Sum, rounded to a whole point						−62

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,331	2411.1	− 2436	−24.9	× 30 / 152	−4.9
4	41,332	2460.4	− 2485	−24.6	× 18 / 152	−2.9
5	41,333	2457.7	− 2528	−70.3	× 22 / 152	−10.2
6	41,334	2537.5	− 2552	−14.5	× 17 / 152	−1.6
7	41,335	2481.1	− 2567	−85.9	× 24 / 152	−13.6
8	41,336	2488.6	− 2586	−97.4	× 28 / 152	−17.9
11	41,337	2415.3	− 2628	−212.7	× 13 / 152	−18.2
Sum, rounded to a whole point						−69

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	41,148	2385.4	− 2436	−50.6	× 14 / 144	−4.9
4	41,149	2480.9	− 2485	−4.1	× 27 / 144	−0.8
5	41,150	2485.0	− 2528	−43	× 19 / 144	−5.7
6	41,151	2505.1	− 2552	−46.9	× 21 / 144	−6.8
7	41,152	2506.2	− 2567	−60.8	× 17 / 144	−7.2
8	41,153	2482.5	− 2586	−103.5	× 24 / 144	−17.3
11	41,154	2513.4	− 2628	−114.6	× 22 / 144	−17.5
Sum, rounded to a whole point						−60

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	40,913	2392.4	− 2436	−43.6	× 18 / 136	−5.8
4	40,914	2417.0	− 2485	−68	× 15 / 136	−7.5
5	40,915	2500.5	− 2528	−27.5	× 26 / 136	−5.3
6	40,916	2513.3	− 2552	−38.7	× 18 / 136	−5.1
7	40,917	2497.4	− 2567	−69.6	× 19 / 136	−9.7
8	40,918	2515.9	− 2586	−70.1	× 21 / 136	−10.8
11	40,919	2430.8	− 2628	−197.2	× 19 / 136	−27.6
Sum, rounded to a whole point						−72

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −51, −76, −73, −62, −60, −62, −69, −60, −72 → −65
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 25 · 2016→2017: 3 · 2017→2018: 11 · 2018→2019: 2 · 2019→2022: 2 · 2022→2023: 7 · 2023→2024: 9 · 2024→2025: 12 → average 8.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 8.9 × 2.66 = 23.7. Upper limit −41.3, lower limit −88.7.

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 — for a district, the total across its schools. From 2014–15, 2015–16, 2016–17, 2017–18, 2018–19, 2020–21, 2021–22, 2022–23, 2023–24, 2024–25, 2025–26.