San Luis Obispo: math

The shaded band is this county'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	81,471	2425.2	− 2436	−10.8	× 2511 / 17594	−1.5
4	81,472	2466.6	− 2485	−18.4	× 2481 / 17594	−2.6
5	81,475	2496.1	− 2528	−31.9	× 2636 / 17594	−4.8
6	81,476	2522.2	− 2552	−29.8	× 2585 / 17594	−4.4
7	81,479	2535.5	− 2567	−31.5	× 2419 / 17594	−4.3
8	81,481	2541.9	− 2586	−44.1	× 2498 / 17594	−6.3
11	81,482	2549.9	− 2628	−78.1	× 2464 / 17594	−10.9
Sum, rounded to a whole point						−35

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	75,523	2436.3	− 2436	0.3	× 2623 / 17882	0
4	75,525	2475.6	− 2485	−9.4	× 2535 / 17882	−1.3
5	75,526	2505.3	− 2528	−22.7	× 2519 / 17882	−3.2
6	75,528	2532.5	− 2552	−19.5	× 2637 / 17882	−2.9
7	75,531	2543.4	− 2567	−23.6	× 2590 / 17882	−3.4
8	75,532	2558.5	− 2586	−27.5	× 2433 / 17882	−3.7
11	75,534	2565.2	− 2628	−62.8	× 2545 / 17882	−8.9
Sum, rounded to a whole point						−23

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	77,542	2434.3	− 2436	−1.7	× 2454 / 18023	−0.2
4	77,543	2475.0	− 2485	−10	× 2635 / 18023	−1.5
5	77,545	2502.4	− 2528	−25.6	× 2528 / 18023	−3.6
6	77,548	2528.6	− 2552	−23.4	× 2602 / 18023	−3.4
7	77,550	2544.1	− 2567	−22.9	× 2628 / 18023	−3.3
8	77,551	2555.5	− 2586	−30.5	× 2546 / 18023	−4.3
11	77,553	2573.9	− 2628	−54.1	× 2630 / 18023	−7.9
Sum, rounded to a whole point						−24

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	77,727	2442.0	− 2436	6	× 2354 / 17748	0.8
4	77,728	2473.9	− 2485	−11.1	× 2455 / 17748	−1.5
5	77,731	2505.1	− 2528	−22.9	× 2624 / 17748	−3.4
6	77,732	2532.6	− 2552	−19.4	× 2526 / 17748	−2.8
7	77,735	2542.9	− 2567	−24.1	× 2564 / 17748	−3.5
8	77,736	2560.2	− 2586	−25.8	× 2639 / 17748	−3.8
11	77,739	2567.3	− 2628	−60.7	× 2586 / 17748	−8.8
Sum, rounded to a whole point						−23

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,262	2446.4	− 2436	10.4	× 2461 / 17551	1.5
4	78,263	2486.3	− 2485	1.3	× 2361 / 17551	0.2
5	78,264	2505.0	− 2528	−23	× 2455 / 17551	−3.2
6	78,265	2528.2	− 2552	−23.8	× 2641 / 17551	−3.6
7	78,266	2548.8	− 2567	−18.2	× 2566 / 17551	−2.7
8	78,267	2565.5	− 2586	−20.5	× 2512 / 17551	−2.9
11	78,268	2575.1	− 2628	−52.9	× 2555 / 17551	−7.7
Sum, rounded to a whole point						−18

2021 from sb_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	76,809	2436.9	− 2436	0.9	× 544 / 4712	0.1
4	76,810	2489.3	− 2485	4.3	× 658 / 4712	0.6
5	76,811	2504.9	− 2528	−23.1	× 666 / 4712	−3.3
6	76,812	2535.2	− 2552	−16.8	× 629 / 4712	−2.2
7	76,813	2555.2	− 2567	−11.8	× 576 / 4712	−1.4
8	76,814	2579.9	− 2586	−6.1	× 579 / 4712	−0.7
11	76,815	2566.4	− 2628	−61.6	× 1060 / 4712	−13.9
Sum, rounded to a whole point						−21

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,492	2430.3	− 2436	−5.7	× 2204 / 16337	−0.8
4	78,493	2469.9	− 2485	−15.1	× 2271 / 16337	−2.1
5	78,494	2489.1	− 2528	−38.9	× 2385 / 16337	−5.7
6	78,495	2518.2	− 2552	−33.8	× 2380 / 16337	−4.9
7	78,496	2527.0	− 2567	−40	× 2248 / 16337	−5.5
8	78,497	2538.8	− 2586	−47.2	× 2369 / 16337	−6.8
11	78,498	2551.2	− 2628	−76.8	× 2480 / 16337	−11.7
Sum, rounded to a whole point						−37

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,492	2433.5	− 2436	−2.5	× 2184 / 16230	−0.3
4	78,493	2471.9	− 2485	−13.1	× 2203 / 16230	−1.8
5	78,494	2496.1	− 2528	−31.9	× 2271 / 16230	−4.5
6	78,495	2513.2	− 2552	−38.8	× 2418 / 16230	−5.8
7	78,496	2535.4	− 2567	−31.6	× 2363 / 16230	−4.6
8	78,497	2537.6	− 2586	−48.4	× 2238 / 16230	−6.7
11	78,498	2549.6	− 2628	−78.4	× 2553 / 16230	−12.3
Sum, rounded to a whole point						−36

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,524	2433.3	− 2436	−2.7	× 2244 / 16604	−0.4
4	78,525	2472.5	− 2485	−12.5	× 2276 / 16604	−1.7
5	78,526	2498.3	− 2528	−29.7	× 2286 / 16604	−4.1
6	78,527	2519.7	− 2552	−32.3	× 2307 / 16604	−4.5
7	78,528	2525.4	− 2567	−41.6	× 2429 / 16604	−6.1
8	78,529	2545.6	− 2586	−40.4	× 2370 / 16604	−5.8
11	78,530	2543.9	− 2628	−84.1	× 2692 / 16604	−13.6
Sum, rounded to a whole point						−36

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,196	2432.5	− 2436	−3.5	× 2229 / 16509	−0.5
4	78,197	2475.0	− 2485	−10	× 2290 / 16509	−1.4
5	78,198	2496.4	− 2528	−31.6	× 2315 / 16509	−4.4
6	78,199	2523.1	− 2552	−28.9	× 2300 / 16509	−4
7	78,200	2532.9	− 2567	−34.1	× 2330 / 16509	−4.8
8	78,201	2543.0	− 2586	−43	× 2426 / 16509	−6.3
11	78,202	2556.9	− 2628	−71.1	× 2619 / 16509	−11.3
Sum, rounded to a whole point						−33

2026 from sb_ca2026_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,100	2430.7	− 2436	−5.3	× 2174 / 16072	−0.7
4	78,101	2475.8	− 2485	−9.2	× 2249 / 16072	−1.3
5	78,102	2498.4	− 2528	−29.6	× 2294 / 16072	−4.2
6	78,103	2519.9	− 2552	−32.1	× 2324 / 16072	−4.6
7	78,104	2536.9	− 2567	−30.1	× 2289 / 16072	−4.3
8	78,105	2546.3	− 2586	−39.7	× 2330 / 16072	−5.8
11	78,106	2558.3	− 2628	−69.7	× 2412 / 16072	−10.5
Sum, rounded to a whole point						−31

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −35, −23, −24, −23, −18, −21, −37, −36, −36, −33, −31 → −28.8
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 12 · 2016→2017: 1 · 2017→2018: 1 · 2018→2019: 5 · 2019→2021: 3 · 2021→2022: 16 · 2022→2023: 1 · 2023→2024: 0 · 2024→2025: 3 · 2025→2026: 2 → average 4.4
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 4.4 × 2.66 = 11.7. Upper limit −17.1, lower limit −40.5.

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 county, 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.