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1. 1
   How it was computedvalue = published '% with 90%+ Attendance (Yearly)'; denominator = published 'Total Students (Yearly)'

   1. Read the district's school-level attendance CSV.
   2. Keep rows for district-run schools in the directory; map the file's Category/Group columns to subgroups (all students, race/ethnicity, gender). Grade-level rows are not stored.
   3. Store the published percentage and student count; suppressed cells are flagged, not zeroed.

   Algorithms applied downstream: Chronic absenteeism as 100 minus the 90%-attendance share, Citywide and peer-group percentiles, Peer groups: 40 nearest neighbors on demographics

2. 2
   The load that wrote it1 data load wrote this metric

   Loaded	Source file	Years	Cells	Suppressed	File hash	Commit
   2026-06-04	sdp_attendance_90_school	2020-21, 2021-22, 2022-23, 2023-24, 2024-25	9,595	2,932	552bf3bd6d53…	f75e3313

   The hash identifies the exact file version read; the commit identifies the exact code. Both are recorded at load time.

   Evidence: sdp_attendance_and_suspensions.ts

3. 3
   The publisher's fileStudent attendance — % with 90%+ attendance, by school and year

   Student attendance — % with 90%+ attendance, by school and year — School District of Philadelphia (Performance Office). For each school and year, the number and share of students who attended at least 90% of their enrolled days, for all students and by grade, race/ethnicity, and gender. District-run schools only.

   format

   CSV

   join key

   ULCS Code

   landing page

   https://opendataphilly.org/datasets/sdp-school-performance/

   • District sector only — no charter, cyber, contracted, or alternative schools.
   • Small groups are suppressed; from 2021-22 one of Male/Female is also suppressed wherever Non-Binary is, including at large high schools.
   • Denominator ('Total Students (Yearly)') counts students enrolled at least 10 days at the school; a student enrolled 10+ days at two schools is counted at each (SDP, Student Attendance Patterns in Philadelphia 2017-18 to 2021-22, June 2023). Summed across schools it is a count of student records, not distinct students.

   Evidence: source registry (sources.yaml) · sdp_attendance_90_school: first-fetch findings

4. 4
   How it was checkedChecks: 3 passed, 1 flagged

   • ✓ passedBase case: 216 of 216 served 2024-25 cells match an independent re-read of the file
   • ✓ passedCompleteness: every source cell is served for directory schools
   • ⚠ flaggedCross-publisher vs the state's Regular Attendance figure for the same schools and attendance year: closely correlated, not interchangeable (median and per-year values in the report)
   • ✓ passedFull QA: every served cell (value and student count), every year and subgroup, matches a re-read of the district file

   compared

   216 cells (All students, n/a)

   tolerance

   ±0.5

   mismatches

   0

   served only

   0

   source only

   0

   Year	Cut	Source cells	Served cells	Source-only	Served-only
   2024-25	n/a	216	216	0	0

   Evidence: Base case · Completeness · Cross-publisher vs the state's Regular Attendance figure for the same schools and attendance year · Full QA

5. 5
   Assumptions & caveatsAssumptions and caveats

   Assumptions

   • '90%+ attendance' is read as the complement of chronic absenteeism: attending less than 90% of enrolled days. A student at exactly 90% is in the 90%+ group (and so outside the below-90 share) but chronically absent under the federal 'missed 10% or more' definition; the district does not document rounding at that boundary.
   • Minimum enrollment: 10 days at the school, with transfers attributed to each qualifying school (SDP, June 2023 attendance report).

   Caveats

   • District-run schools only.
   • Schools closed before 2024-25 are absent from the served table (their rows exist in the source file and are included in the working-analysis packet).

To see the tree for one school’s number, click any dotted-underlined figure on a school, Outliers, or Movers page.