Marin: english · Schoolio

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	41,793	2446.4	− 2432	14.4	× 2626 / 17111	2.2
4	41,796	2498.6	− 2473	25.6	× 2586 / 17111	3.9
5	41,797	2533.8	− 2502	31.8	× 2632 / 17111	4.9
6	41,800	2557.7	− 2531	26.7	× 2541 / 17111	4
7	41,801	2579.0	− 2552	27	× 2465 / 17111	3.9
8	41,804	2596.3	− 2567	29.3	× 2308 / 17111	4
11	41,805	2628.3	− 2583	45.3	× 1953 / 17111	5.2
Sum, rounded to a whole point						28

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	38,671	2455.0	− 2432	23	× 2586 / 17504	3.4
4	38,674	2501.0	− 2473	28	× 2649 / 17504	4.2
5	38,675	2543.5	− 2502	41.5	× 2584 / 17504	6.1
6	38,677	2559.3	− 2531	28.3	× 2622 / 17504	4.2
7	38,679	2588.4	− 2552	36.4	× 2565 / 17504	5.3
8	38,682	2606.4	− 2567	39.4	× 2465 / 17504	5.5
11	38,684	2618.8	− 2583	35.8	× 2033 / 17504	4.2
Sum, rounded to a whole point						33

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	39,611	2446.1	− 2432	14.1	× 2543 / 17563	2
4	39,613	2494.1	− 2473	21.1	× 2556 / 17563	3.1
5	39,615	2531.5	− 2502	29.5	× 2641 / 17563	4.4
6	39,616	2558.2	− 2531	27.2	× 2508 / 17563	3.9
7	39,619	2586.9	− 2552	34.9	× 2575 / 17563	5.1
8	39,620	2598.9	− 2567	31.9	× 2502 / 17563	4.5
11	39,622	2625.4	− 2583	42.4	× 2238 / 17563	5.4
Sum, rounded to a whole point						28

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	39,636	2452.6	− 2432	20.6	× 2479 / 17604	2.9
4	39,637	2498.3	− 2473	25.3	× 2548 / 17604	3.7
5	39,640	2537.3	− 2502	35.3	× 2560 / 17604	5.1
6	39,641	2551.6	− 2531	20.6	× 2570 / 17604	3
7	39,644	2585.8	− 2552	33.8	× 2486 / 17604	4.8
8	39,645	2597.4	− 2567	30.4	× 2580 / 17604	4.5
11	39,648	2617.1	− 2583	34.1	× 2381 / 17604	4.6
Sum, rounded to a whole point						29

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	39,787	2455.2	− 2432	23.2	× 2365 / 17121	3.2
4	39,788	2500.3	− 2473	27.3	× 2462 / 17121	3.9
5	39,789	2535.9	− 2502	33.9	× 2510 / 17121	5
6	39,790	2559.8	− 2531	28.8	× 2488 / 17121	4.2
7	39,791	2588.1	− 2552	36.1	× 2565 / 17121	5.4
8	39,792	2603.0	− 2567	36	× 2442 / 17121	5.1
11	39,793	2611.2	− 2583	28.2	× 2289 / 17121	3.8
Sum, rounded to a whole point						31

2021 from sb_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	38,764	2423.6	− 2432	−8.4	× 1497 / 11347	−1.1
4	38,765	2464.8	− 2473	−8.2	× 1510 / 11347	−1.1
5	38,766	2517.6	− 2502	15.6	× 1511 / 11347	2.1
6	38,767	2528.5	− 2531	−2.5	× 1519 / 11347	−0.3
7	38,768	2561.8	− 2552	9.8	× 1583 / 11347	1.4
8	38,769	2581.2	− 2567	14.2	× 1569 / 11347	2
11	38,770	2626.9	− 2583	43.9	× 2158 / 11347	8.3
Sum, rounded to a whole point						11

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	39,570	2442.7	− 2432	10.7	× 2071 / 15106	1.5
4	39,571	2492.1	− 2473	19.1	× 2109 / 15106	2.7
5	39,572	2521.9	− 2502	19.9	× 2160 / 15106	2.8
6	39,573	2547.5	− 2531	16.5	× 2084 / 15106	2.3
7	39,574	2581.8	− 2552	29.8	× 2204 / 15106	4.3
8	39,575	2593.5	− 2567	26.5	× 2295 / 15106	4
11	39,576	2616.9	− 2583	33.9	× 2183 / 15106	4.9
Sum, rounded to a whole point						23

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	39,631	2438.7	− 2432	6.7	× 2126 / 14804	1
4	39,632	2492.4	− 2473	19.4	× 2048 / 14804	2.7
5	39,633	2526.3	− 2502	24.3	× 2128 / 14804	3.5
6	39,634	2536.4	− 2531	5.4	× 2031 / 14804	0.7
7	39,635	2577.2	− 2552	25.2	× 2105 / 14804	3.6
8	39,636	2586.5	− 2567	19.5	× 2185 / 14804	2.9
11	39,637	2614.4	− 2583	31.4	× 2181 / 14804	4.6
Sum, rounded to a whole point						19

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	39,448	2438.9	− 2432	6.9	× 2101 / 14902	1
4	39,449	2487.3	− 2473	14.3	× 2130 / 14902	2
5	39,450	2533.3	− 2502	31.3	× 2054 / 14902	4.3
6	39,451	2542.4	− 2531	11.4	× 2097 / 14902	1.6
7	39,452	2571.4	− 2552	19.4	× 2040 / 14902	2.7
8	39,453	2592.9	− 2567	25.9	× 2116 / 14902	3.7
11	39,454	2613.0	− 2583	30	× 2364 / 14902	4.8
Sum, rounded to a whole point						20

2025 from sb_ca2025_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	39,223	2441.3	− 2432	9.3	× 2010 / 14804	1.3
4	39,224	2491.7	− 2473	18.7	× 2117 / 14804	2.7
5	39,225	2532.3	− 2502	30.3	× 2136 / 14804	4.4
6	39,226	2555.8	− 2531	24.8	× 2007 / 14804	3.4
7	39,227	2583.3	− 2552	31.3	× 2119 / 14804	4.5
8	39,228	2589.1	− 2567	22.1	× 2070 / 14804	3.1
11	39,229	2605.1	− 2583	22.1	× 2345 / 14804	3.5
Sum, rounded to a whole point						23

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. 28, 33, 28, 29, 31, 11, 23, 19, 20, 23 → 24.5
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 5 · 2016→2017: 5 · 2017→2018: 1 · 2018→2019: 2 · 2019→2021: 20 · 2021→2022: 12 · 2022→2023: 4 · 2023→2024: 1 · 2024→2025: 3 → average 5.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 5.9 × 2.66 = 15.7. Upper limit 40.2, lower limit 8.8.

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.