Marengo Ranch 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	61,011	2421.5	− 2436	−14.5	× 80 / 352	−3.3
4	61,013	2413.7	− 2485	−71.3	× 91 / 352	−18.4
5	61,015	2460.6	− 2528	−67.4	× 98 / 352	−18.8
6	61,017	2518.8	− 2552	−33.2	× 83 / 352	−7.8
Sum, rounded to a whole point						−48

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	56,601	2421.1	− 2436	−14.9	× 65 / 350	−2.8
4	56,603	2449.0	− 2485	−36	× 91 / 350	−9.4
5	56,605	2474.2	− 2528	−53.8	× 93 / 350	−14.3
6	56,607	2512.1	− 2552	−39.9	× 101 / 350	−11.5
Sum, rounded to a whole point						−38

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,245	2416.2	− 2436	−19.8	× 71 / 329	−4.3
4	58,247	2452.3	− 2485	−32.7	× 67 / 329	−6.7
5	58,249	2479.5	− 2528	−48.5	× 95 / 329	−14
6	58,251	2487.1	− 2552	−64.9	× 96 / 329	−18.9
Sum, rounded to a whole point						−44

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,377	2427.3	− 2436	−8.7	× 66 / 292	−2
4	58,380	2457.9	− 2485	−27.1	× 67 / 292	−6.2
5	58,381	2501.2	− 2528	−26.8	× 64 / 292	−5.9
6	58,384	2516.7	− 2552	−35.3	× 95 / 292	−11.5
Sum, rounded to a whole point						−26

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,621	2431.7	− 2436	−4.3	× 86 / 296	−1.2
4	58,622	2455.2	− 2485	−29.8	× 70 / 296	−7
5	58,623	2507.0	− 2528	−21	× 68 / 296	−4.8
6	58,624	2509.5	− 2552	−42.5	× 72 / 296	−10.3
Sum, rounded to a whole point						−23

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,696	2439.5	− 2436	3.5	× 72 / 312	0.8
4	58,697	2470.7	− 2485	−14.3	× 89 / 312	−4.1
5	58,698	2520.9	− 2528	−7.1	× 64 / 312	−1.5
6	58,699	2492.8	− 2552	−59.2	× 87 / 312	−16.5
Sum, rounded to a whole point						−21

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,654	2440.1	− 2436	4.1	× 70 / 292	1
4	58,655	2478.5	− 2485	−6.5	× 74 / 292	−1.6
5	58,656	2534.1	− 2528	6.1	× 81 / 292	1.7
6	58,657	2542.9	− 2552	−9.1	× 67 / 292	−2.1
Sum, rounded to a whole point						−1

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,565	2448.2	− 2436	12.2	× 57 / 299	2.3
4	58,566	2459.1	− 2485	−25.9	× 72 / 299	−6.2
5	58,567	2484.8	− 2528	−43.2	× 83 / 299	−12
6	58,568	2540.1	− 2552	−11.9	× 87 / 299	−3.5
Sum, rounded to a whole point						−19

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	58,322	2457.4	− 2436	21.4	× 59 / 265	4.8
4	58,323	2466.2	− 2485	−18.8	× 57 / 265	−4
5	58,324	2500.0	− 2528	−28	× 72 / 265	−7.6
6	58,325	2517.2	− 2552	−34.8	× 77 / 265	−10.1
Sum, rounded to a whole point						−17

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −48, −38, −44, −26, −23, −21, −1, −19, −17 → −26.3
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 10 · 2016→2017: 6 · 2017→2018: 18 · 2018→2019: 3 · 2019→2022: 2 · 2022→2023: 20 · 2023→2024: 18 · 2024→2025: 2 → average 9.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 9.9 × 2.66 = 26.3. Upper limit 0, lower limit −52.6.

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.