San Mateo: english

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	82,348	2430.0	− 2432	−2	× 7554 / 48747	−0.3
4	82,351	2477.1	− 2473	4.1	× 7336 / 48747	0.6
5	82,352	2514.9	− 2502	12.9	× 7277 / 48747	1.9
6	82,354	2537.6	− 2531	6.6	× 7148 / 48747	1
7	82,356	2562.4	− 2552	10.4	× 6890 / 48747	1.5
8	82,359	2580.3	− 2567	13.3	× 6688 / 48747	1.8
11	82,360	2615.8	− 2583	32.8	× 5854 / 48747	3.9
Sum, rounded to a whole point						10

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	76,379	2440.9	− 2432	8.9	× 7136 / 49322	1.3
4	76,381	2481.0	− 2473	8	× 7479 / 49322	1.2
5	76,382	2523.9	− 2502	21.9	× 7224 / 49322	3.2
6	76,385	2547.1	− 2531	16.1	× 7192 / 49322	2.3
7	76,387	2570.2	− 2552	18.2	× 7058 / 49322	2.6
8	76,388	2587.1	− 2567	20.1	× 6870 / 49322	2.8
11	76,390	2620.5	− 2583	37.5	× 6363 / 49322	4.8
Sum, rounded to a whole point						18

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,419	2438.8	− 2432	6.8	× 7106 / 49218	1
4	78,422	2482.1	− 2473	9.1	× 7033 / 49218	1.3
5	78,424	2516.5	− 2502	14.5	× 7365 / 49218	2.2
6	78,425	2545.0	− 2531	14	× 7001 / 49218	2
7	78,428	2574.7	− 2552	22.7	× 7071 / 49218	3.3
8	78,429	2587.2	− 2567	20.2	× 6953 / 49218	2.9
11	78,432	2631.7	− 2583	48.7	× 6689 / 49218	6.6
Sum, rounded to a whole point						19

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	78,570	2447.1	− 2432	15.1	× 6731 / 48245	2.1
4	78,573	2490.7	− 2473	17.7	× 6996 / 48245	2.6
5	78,574	2523.8	− 2502	21.8	× 6974 / 48245	3.2
6	78,577	2542.9	− 2531	11.9	× 7210 / 48245	1.8
7	78,578	2575.7	− 2552	23.7	× 6932 / 48245	3.4
8	78,581	2594.2	− 2567	27.2	× 7081 / 48245	4
11	78,582	2616.5	− 2583	33.5	× 6321 / 48245	4.4
Sum, rounded to a whole point						21

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	79,098	2448.6	− 2432	16.6	× 7017 / 47973	2.4
4	79,099	2493.9	− 2473	20.9	× 6569 / 47973	2.9
5	79,100	2528.1	− 2502	26.1	× 6915 / 47973	3.8
6	79,101	2548.5	− 2531	17.5	× 6761 / 47973	2.5
7	79,102	2576.8	− 2552	24.8	× 7144 / 47973	3.7
8	79,103	2593.0	− 2567	26	× 6965 / 47973	3.8
11	79,104	2621.9	− 2583	38.9	× 6602 / 47973	5.4
Sum, rounded to a whole point						24

2021 from sb_ca2021_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	77,655	2443.7	− 2432	11.7	× 4555 / 27546	1.9
4	77,656	2484.3	− 2473	11.3	× 4543 / 27546	1.9
5	77,657	2529.0	− 2502	27	× 4621 / 27546	4.5
6	77,658	2549.6	− 2531	18.6	× 4227 / 27546	2.9
7	77,659	2580.7	− 2552	28.7	× 4316 / 27546	4.5
8	77,660	2594.4	− 2567	27.4	× 4324 / 27546	4.3
11	77,661	2627.8	− 2583	44.8	× 960 / 27546	1.6
Sum, rounded to a whole point						22

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	79,354	2440.1	− 2432	8.1	× 6150 / 43173	1.2
4	79,355	2484.0	− 2473	11	× 6259 / 43173	1.6
5	79,356	2521.4	− 2502	19.4	× 6391 / 43173	2.9
6	79,357	2535.4	− 2531	4.4	× 6170 / 43173	0.6
7	79,358	2576.5	− 2552	24.5	× 5991 / 43173	3.4
8	79,359	2585.8	− 2567	18.8	× 6233 / 43173	2.7
11	79,360	2629.5	− 2583	46.5	× 5979 / 43173	6.4
Sum, rounded to a whole point						19

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	79,324	2441.4	− 2432	9.4	× 5926 / 42982	1.3
4	79,325	2481.1	− 2473	8.1	× 6145 / 42982	1.2
5	79,326	2520.5	− 2502	18.5	× 6206 / 42982	2.7
6	79,327	2534.6	− 2531	3.6	× 6186 / 42982	0.5
7	79,328	2566.7	− 2552	14.7	× 6131 / 42982	2.1
8	79,329	2583.4	− 2567	16.4	× 5990 / 42982	2.3
11	79,330	2622.7	− 2583	39.7	× 6398 / 42982	5.9
Sum, rounded to a whole point						16

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	79,364	2437.8	− 2432	5.8	× 5851 / 42470	0.8
4	79,365	2481.3	− 2473	8.3	× 5925 / 42470	1.2
5	79,366	2517.4	− 2502	15.4	× 6139 / 42470	2.2
6	79,367	2536.9	− 2531	5.9	× 6003 / 42470	0.8
7	79,368	2568.3	− 2552	16.3	× 6230 / 42470	2.4
8	79,369	2579.2	− 2567	12.2	× 6129 / 42470	1.8
11	79,370	2618.1	− 2583	35.1	× 6193 / 42470	5.1
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	79,030	2434.9	− 2432	2.9	× 5837 / 42352	0.4
4	79,031	2483.1	− 2473	10.1	× 5960 / 42352	1.4
5	79,032	2520.8	− 2502	18.8	× 6006 / 42352	2.7
6	79,033	2540.5	− 2531	9.5	× 6056 / 42352	1.4
7	79,034	2567.4	− 2552	15.4	× 6090 / 42352	2.2
8	79,035	2584.9	− 2567	17.9	× 6290 / 42352	2.7
11	79,036	2621.6	− 2583	38.6	× 6113 / 42352	5.6
Sum, rounded to a whole point						16

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. 10, 18, 19, 21, 24, 22, 19, 16, 14, 16 → 17.9
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 8 · 2016→2017: 1 · 2017→2018: 2 · 2018→2019: 3 · 2019→2021: 2 · 2021→2022: 3 · 2022→2023: 3 · 2023→2024: 2 · 2024→2025: 2 → average 2.9
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 2.9 × 2.66 = 7.7. Upper limit 25.6, lower limit 10.2.

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.