Potrero 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	72,699	2372.1	− 2436	−63.9	× 28 / 190	−9.4
4	72,701	2405.7	− 2485	−79.3	× 27 / 190	−11.3
5	72,703	2418.6	− 2528	−109.4	× 36 / 190	−20.7
6	72,705	2419.7	− 2552	−132.3	× 31 / 190	−21.6
7	72,707	2468.4	− 2567	−98.6	× 33 / 190	−17.1
8	72,709	2443.1	− 2586	−142.9	× 35 / 190	−26.3
Sum, rounded to a whole point						−106

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	67,474	2378.6	− 2436	−57.4	× 28 / 197	−8.2
4	67,476	2425.4	− 2485	−59.6	× 27 / 197	−8.2
5	67,478	2433.0	− 2528	−95	× 31 / 197	−14.9
6	67,481	2432.4	− 2552	−119.6	× 43 / 197	−26.1
7	67,482	2433.6	− 2567	−133.4	× 32 / 197	−21.7
8	67,485	2453.2	− 2586	−132.8	× 36 / 197	−24.3
Sum, rounded to a whole point						−103

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	69,256	2367.3	− 2436	−68.7	× 47 / 215	−15
4	69,258	2396.1	− 2485	−88.9	× 36 / 215	−14.9
5	69,259	2427.8	− 2528	−100.2	× 28 / 215	−13
6	69,262	2431.5	− 2552	−120.5	× 36 / 215	−20.2
7	69,263	2450.5	− 2567	−116.5	× 41 / 215	−22.2
8	69,265	2443.2	− 2586	−142.8	× 27 / 215	−17.9
Sum, rounded to a whole point						−103

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	69,437	2379.3	− 2436	−56.7	× 33 / 141	−13.3
4	69,439	2448.9	− 2485	−36.1	× 40 / 141	−10.2
5	69,440	2439.0	− 2528	−89	× 40 / 141	−25.2
6	69,443	2449.3	− 2552	−102.7	× 28 / 141	−20.4
Sum, rounded to a whole point						−69

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	69,961	2336.6	− 2436	−99.4	× 44 / 169	−25.9
4	69,962	2408.1	− 2485	−76.9	× 38 / 169	−17.3
5	69,963	2448.0	− 2528	−80	× 41 / 169	−19.4
6	69,964	2428.6	− 2552	−123.4	× 46 / 169	−33.6
Sum, rounded to a whole point						−96

2021 from sb_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	68,484	2356.6	− 2436	−79.4	× 32 / 157	−16.2
4	68,485	2372.9	− 2485	−112.1	× 52 / 157	−37.1
5	68,486	2374.2	− 2528	−153.8	× 39 / 157	−38.2
6	68,487	2454.7	− 2552	−97.3	× 34 / 157	−21.1
Sum, rounded to a whole point						−113

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	70,053	2358.5	− 2436	−77.5	× 54 / 207	−20.2
4	70,054	2405.0	− 2485	−80	× 41 / 207	−15.8
5	70,055	2415.4	− 2528	−112.6	× 64 / 207	−34.8
6	70,056	2470.1	− 2552	−81.9	× 48 / 207	−19
Sum, rounded to a whole point						−90

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	70,059	2349.2	− 2436	−86.8	× 34 / 201	−14.7
4	70,060	2380.7	− 2485	−104.3	× 60 / 201	−31.1
5	70,061	2390.5	− 2528	−137.5	× 41 / 201	−28
6	70,062	2411.5	− 2552	−140.5	× 66 / 201	−46.1
Sum, rounded to a whole point						−120

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	70,041	2352.4	− 2436	−83.6	× 43 / 173	−20.8
4	70,042	2392.8	− 2485	−92.2	× 36 / 173	−19.2
5	70,043	2449.6	− 2528	−78.4	× 56 / 173	−25.4
6	70,044	2416.0	− 2552	−136	× 38 / 173	−29.9
Sum, rounded to a whole point						−95

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	69,751	2343.1	− 2436	−92.9	× 44 / 172	−23.8
4	69,752	2392.8	− 2485	−92.2	× 38 / 172	−20.4
5	69,753	2417.5	− 2528	−110.5	× 37 / 172	−23.8
6	69,754	2428.8	− 2552	−123.2	× 53 / 172	−38
Sum, rounded to a whole point						−106

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −106, −103, −103, −69, −96, −113, −90, −120, −95, −106 → −100.1
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 3 · 2016→2017: 0 · 2017→2018: 34 · 2018→2019: 27 · 2019→2021: 17 · 2021→2022: 23 · 2022→2023: 30 · 2023→2024: 25 · 2024→2025: 11 → average 18.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 18.9 × 2.66 = 50.3. Upper limit −49.8, lower limit −150.4.

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.