Bridgeway Island 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	105,523	2448.5	− 2436	12.5	× 127 / 635	2.5
4	105,526	2463.7	− 2485	−21.3	× 103 / 635	−3.5
5	105,527	2500.8	− 2528	−27.2	× 104 / 635	−4.5
6	105,530	2538.1	− 2552	−13.9	× 105 / 635	−2.3
7	105,531	2583.6	− 2567	16.6	× 100 / 635	2.6
8	105,533	2605.3	− 2586	19.3	× 96 / 635	2.9
Sum, rounded to a whole point						−2

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	98,035	2457.4	− 2436	21.4	× 111 / 665	3.6
4	98,038	2490.8	− 2485	5.8	× 125 / 665	1.1
5	98,040	2516.1	− 2528	−11.9	× 104 / 665	−1.9
6	98,041	2506.1	− 2552	−45.9	× 111 / 665	−7.7
7	98,044	2568.6	− 2567	1.6	× 120 / 665	0.3
8	98,045	2606.7	− 2586	20.7	× 94 / 665	2.9
Sum, rounded to a whole point						−2

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	100,900	2465.4	− 2436	29.4	× 123 / 692	5.2
4	100,903	2489.2	− 2485	4.2	× 116 / 692	0.7
5	100,905	2514.4	− 2528	−13.6	× 126 / 692	−2.5
6	100,906	2536.9	− 2552	−15.1	× 102 / 692	−2.2
7	100,909	2562.9	− 2567	−4.1	× 103 / 692	−0.6
8	100,911	2565.6	− 2586	−20.4	× 122 / 692	−3.6
Sum, rounded to a whole point						−3

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	101,056	2467.8	− 2436	31.8	× 115 / 701	5.2
4	101,058	2493.1	− 2485	8.1	× 127 / 701	1.5
5	101,059	2518.3	− 2528	−9.7	× 117 / 701	−1.6
6	101,061	2549.8	− 2552	−2.2	× 124 / 701	−0.4
7	101,063	2566.4	− 2567	−0.6	× 103 / 701	−0.1
8	101,065	2588.5	− 2586	2.5	× 115 / 701	0.4
Sum, rounded to a whole point						5

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	101,703	2445.3	− 2436	9.3	× 119 / 692	1.6
4	101,704	2498.7	− 2485	13.7	× 110 / 692	2.2
5	101,705	2523.7	− 2528	−4.3	× 127 / 692	−0.8
6	101,706	2550.4	− 2552	−1.6	× 114 / 692	−0.3
7	101,707	2563.1	− 2567	−3.9	× 123 / 692	−0.7
8	101,708	2604.5	− 2586	18.5	× 99 / 692	2.6
Sum, rounded to a whole point						5

2022 from sb_ca2022_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	101,980	2434.9	− 2436	−1.1	× 115 / 692	−0.2
4	101,981	2460.2	− 2485	−24.8	× 121 / 692	−4.3
5	101,982	2511.4	− 2528	−16.6	× 123 / 692	−3
6	101,983	2515.5	− 2552	−36.5	× 117 / 692	−6.2
7	101,984	2536.0	− 2567	−31	× 107 / 692	−4.8
8	101,985	2574.7	− 2586	−11.3	× 109 / 692	−1.8
Sum, rounded to a whole point						−20

2023 from sb_ca2023_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	101,800	2430.7	− 2436	−5.3	× 122 / 733	−0.9
4	101,801	2483.3	− 2485	−1.7	× 121 / 733	−0.3
5	101,802	2466.9	− 2528	−61.1	× 128 / 733	−10.7
6	101,803	2533.6	− 2552	−18.4	× 121 / 733	−3
7	101,804	2541.9	− 2567	−25.1	× 126 / 733	−4.3
8	101,805	2560.8	− 2586	−25.2	× 115 / 733	−4
Sum, rounded to a whole point						−23

2024 from sb_ca2024_1_csv_v1.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	101,687	2444.5	− 2436	8.5	× 125 / 743	1.4
4	101,688	2471.1	− 2485	−13.9	× 127 / 743	−2.4
5	101,689	2505.7	− 2528	−22.3	× 120 / 743	−3.6
6	101,690	2505.0	− 2552	−47	× 124 / 743	−7.8
7	101,691	2547.1	− 2567	−19.9	× 121 / 743	−3.2
8	101,692	2567.9	− 2586	−18.1	× 126 / 743	−3.1
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	101,353	2436.8	− 2436	0.8	× 112 / 723	0.1
4	101,354	2493.9	− 2485	8.9	× 119 / 723	1.5
5	101,355	2507.6	− 2528	−20.4	× 127 / 723	−3.6
6	101,356	2540.4	− 2552	−11.6	× 120 / 723	−1.9
7	101,357	2524.6	− 2567	−42.4	× 124 / 723	−7.3
8	101,358	2557.2	− 2586	−28.8	× 121 / 723	−4.8
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. −2, −2, −3, 5, 5, −20, −23, −19, −16 → −8.3
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 0 · 2016→2017: 1 · 2017→2018: 8 · 2018→2019: 0 · 2019→2022: 25 · 2022→2023: 3 · 2023→2024: 4 · 2024→2025: 3 → average 5.5
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 5.5 × 2.66 = 14.6. Upper limit 6.3, lower limit −22.9.

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.