Del Rio 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	17,821	2420.0	− 2436	−16	× 66 / 229	−4.6
4	17,823	2436.0	− 2485	−49	× 45 / 229	−9.6
5	17,825	2491.8	− 2528	−36.2	× 58 / 229	−9.2
6	17,827	2492.8	− 2552	−59.2	× 60 / 229	−15.5
Sum, rounded to a whole point						−39

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	16,829	2444.5	− 2436	8.5	× 49 / 209	2
4	16,831	2470.8	− 2485	−14.2	× 60 / 209	−4.1
5	16,833	2507.0	− 2528	−21	× 47 / 209	−4.7
6	16,835	2577.8	− 2552	25.8	× 53 / 209	6.5
Sum, rounded to a whole point						0

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	17,152	2437.9	− 2436	1.9	× 47 / 213	0.4
4	17,154	2501.9	− 2485	16.9	× 55 / 213	4.4
5	17,155	2515.3	− 2528	−12.7	× 60 / 213	−3.6
6	17,158	2518.6	− 2552	−33.4	× 51 / 213	−8
Sum, rounded to a whole point						−7

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	17,175	2415.1	− 2436	−20.9	× 48 / 210	−4.8
4	17,176	2512.6	− 2485	27.6	× 46 / 210	6
5	17,179	2528.1	− 2528	0.1	× 57 / 210	0
6	17,180	2531.6	− 2552	−20.4	× 59 / 210	−5.7
Sum, rounded to a whole point						−4

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	17,319	2417.2	− 2436	−18.8	× 72 / 237	−5.7
4	17,320	2481.8	− 2485	−3.2	× 58 / 237	−0.8
5	17,321	2503.6	− 2528	−24.4	× 53 / 237	−5.5
6	17,322	2565.5	− 2552	13.5	× 54 / 237	3.1
Sum, rounded to a whole point						−9

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	17,371	2418.2	− 2436	−17.8	× 72 / 308	−4.2
4	17,372	2500.3	− 2485	15.3	× 86 / 308	4.3
5	17,373	2494.4	− 2528	−33.6	× 68 / 308	−7.4
6	17,374	2527.5	− 2552	−24.5	× 82 / 308	−6.5
Sum, rounded to a whole point						−14

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	17,309	2429.0	− 2436	−7	× 78 / 316	−1.7
4	17,310	2502.0	− 2485	17	× 75 / 316	4
5	17,311	2493.7	− 2528	−34.3	× 90 / 316	−9.8
6	17,312	2527.2	− 2552	−24.8	× 73 / 316	−5.7
Sum, rounded to a whole point						−13

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	17,264	2423.5	− 2436	−12.5	× 83 / 339	−3.1
4	17,265	2496.3	− 2485	11.3	× 80 / 339	2.7
5	17,266	2505.1	− 2528	−22.9	× 79 / 339	−5.3
6	17,267	2522.5	− 2552	−29.5	× 97 / 339	−8.4
Sum, rounded to a whole point						−14

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	17,261	2410.5	− 2436	−25.5	× 79 / 320	−6.3
4	17,262	2495.9	− 2485	10.9	× 82 / 320	2.8
5	17,263	2527.9	− 2528	−0.1	× 79 / 320	0
6	17,264	2519.3	− 2552	−32.7	× 80 / 320	−8.2
Sum, rounded to a whole point						−12

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −39, 0, −7, −4, −9, −14, −13, −14, −12 → −12.4
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 39 · 2016→2017: 7 · 2017→2018: 3 · 2018→2019: 5 · 2019→2022: 5 · 2022→2023: 1 · 2023→2024: 1 · 2024→2025: 2 → average 7.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 7.9 × 2.66 = 21. Upper limit 8.6, lower limit −33.4.

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.