Iftin Charter: 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.

Measured against the grade bars

The state's math test uses one scale for every grade, so a score means the same thing in grade 3 as in grade 8.

3rd The average 3rd grader scores 66 points under the grade 3 bar. 2370 vs. 2436.
4th The average 4th grader scores 18 points under the grade 3 bar. 2418 vs. 2436. The 4th-grade bar is 2485.
5th The average 5th grader scores 31 points under the grade 4 bar. 2454 vs. 2485. The 5th-grade bar is 2528.
6th The average 6th grader scores just under the grade 6 bar. 2544 vs. 2552.
7th The average 7th grader scores 42 points under the grade 5 bar. 2486 vs. 2528. The 7th-grade bar is 2567.
8th The average 8th grader scores 22 points under the grade 5 bar. 2507 vs. 2528. The 8th-grade bar is 2586.

2019 results. "Meets standard" is the state's mark for being on track for that grade.

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	73,533	2407.2	− 2436	−28.8	× 50 / 300	−4.8
4	73,534	2419.1	− 2485	−65.9	× 66 / 300	−14.5
5	73,537	2452.3	− 2528	−75.7	× 48 / 300	−12.1
6	73,538	2509.0	− 2552	−43	× 50 / 300	−7.2
7	73,541	2481.3	− 2567	−85.7	× 51 / 300	−14.6
8	73,542	2527.5	− 2586	−58.5	× 35 / 300	−6.8
Sum, rounded to a whole point						−60

2016 from sb_ca2016_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	68,211	2433.9	− 2436	−2.1	× 47 / 258	−0.4
4	68,212	2439.1	− 2485	−45.9	× 43 / 258	−7.7
5	68,215	2433.8	− 2528	−94.2	× 50 / 258	−18.3
6	68,216	2512.5	− 2552	−39.5	× 40 / 258	−6.1
7	68,218	2515.0	− 2567	−52	× 39 / 258	−7.9
8	68,220	2521.0	− 2586	−65	× 39 / 258	−9.8
Sum, rounded to a whole point						−50

2017 from sb_ca2017_1_csv_v2.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	70,028	2392.1	− 2436	−43.9	× 42 / 276	−6.7
4	70,029	2443.9	− 2485	−41.1	× 48 / 276	−7.1
5	70,032	2438.9	− 2528	−89.1	× 48 / 276	−15.5
6	70,034	2478.4	− 2552	−73.6	× 59 / 276	−15.7
7	70,035	2466.7	− 2567	−100.3	× 38 / 276	−13.8
8	70,037	2491.7	− 2586	−94.3	× 41 / 276	−14
Sum, rounded to a whole point						−73

2018 from sb_ca2018_1_csv_v3.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	70,187	2416.9	− 2436	−19.1	× 30 / 195	−2.9
4	70,189	2429.1	− 2485	−55.9	× 27 / 195	−7.7
5	70,191	2502.3	− 2528	−25.7	× 35 / 195	−4.6
6	70,193	2482.0	− 2552	−70	× 35 / 195	−12.6
7	70,195	2448.7	− 2567	−118.3	× 41 / 195	−24.9
8	70,197	2425.7	− 2586	−160.3	× 27 / 195	−22.2
Sum, rounded to a whole point						−75

2019 from sb_ca2019_1_csv_v4.zip

Grade	Line in file	Average score	Standard Met	Distance	Students	Weighted
3	70,705	2369.9	− 2436	−66.1	× 38 / 224	−11.2
4	70,706	2417.8	− 2485	−67.2	× 31 / 224	−9.3
5	70,707	2454.3	− 2528	−73.7	× 33 / 224	−10.9
6	70,708	2543.8	− 2552	−8.2	× 37 / 224	−1.4
7	70,709	2486.4	− 2567	−80.6	× 39 / 224	−14
8	70,710	2506.5	− 2586	−79.5	× 46 / 224	−16.3
Sum, rounded to a whole point						−63

Step 2 · The average and the normal range

Average: add the yearly results and divide by how many there are. −60, −50, −73, −75, −63 → −64.2
Typical year-to-year change: how far the result moved from each year to the next, ignoring up or down. 2015→2016: 10 · 2016→2017: 23 · 2017→2018: 2 · 2018→2019: 12 → average 11.8
Normal range: multiply the typical change by 2.66, then add it to the average and subtract it. 11.8 × 2.66 = 31.4. Upper limit −32.8, lower limit −95.6.

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".

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.