← All proof trees · MITCHELL ELEMENTARY SCHOOL

1. 1
   What you seePSSA ELA proficiency (all tested grades)

   7.6%

   the share of tested students in grades 3–8 scoring proficient or advanced on the PSSA English language arts test. Based on 92 students.

   vs. peers

   8th percentile

   vs. citywide

   4th percentile

   unit

   percent

   direction

   higher is better

2. 2
   How it was computedvalue = published '% proficient or advanced' (accountability cohort by default)

   1. Unzip the district's PSSA/Keystone archive and read the accountability-cohort ('Acct') and all-tested ('Actual') school CSVs.
   2. Keep rows for the test, subject, grade, and subgroup this metric represents.
   3. Store the published '% proficient or advanced' as the value and the published number tested as the denominator; suppressed cells (asterisks/blanks) are stored as suppressed, not zero.
   4. Store the accountability-cohort cut as the default (population_cut = 'acct') and the all-tested cut alongside it ('actual').

   Citywide percentile, reconstructed right now

   Among 170 default-included schools with a value for this metric, year, and subgroup, this school has a higher value than 6. Midrank rule: (6 + 0/2) / (170 − 1) = 0.036.Stored: 0.036. ✓ matches

   How percentiles are computed · How peer groups are chosen

   Peer percentile, reconstructed right now

   Peer group: up to 40 of the demographically nearest schools among Elementary-Middle / catchment / district schools; 40 of 40 peers have a value this year. This school is above 3 of them. Midrank: (3 + 0/2) / (41 − 1) = 0.075; stored 0.075. ✓ matches

   The peers and their values (40)

   Peer school	Value
   JENKS ACADEMY ARTS & SCIENCES	54.9%
   ANNA L. LINGELBACH SCHOOL	36.6%
   FRANKLIN S. EDMONDS SCHOOL	24.6%
   SAMUEL GOMPERS SCHOOL	24.3%
   OVERBROOK ELEMENTARY SCHOOL	24.2%
   PENROSE SCHOOL	23.9%
   WILLIAM C. BRYANT SCHOOL	22.6%
   A.D. HARRINGTON SCHOOL	22.4%
   GEN. PHILIP KEARNY SCHOOL	22.2%
   JOHN F. MCCLOSKEY SCHOOL	21.6%
   WILLIAM D. KELLEY SCHOOL	20.0%
   PAUL L. DUNBAR SCHOOL	18.6%
   ADD B. ANDERSON SCHOOL	18.4%
   BENJAMIN B. COMEGYS SCHOOL	18.3%
   LEWIS C CASSIDY ACADEMICS PLUS	18.3%
   TANNER DUCKREY SCHOOL	16.7%
   JAMES G. BLAINE SCHOOL	16.5%
   ANNA B. DAY SCHOOL	16.5%
   GUION S. BLUFORD ELEMENTARY SCHOOL	16.3%
   ALAIN LOCKE SCHOOL	15.7%
   JOHN BARRY ELEMENTARY SCHOOL	15.4%
   KENDERTON ELEMENTARY	15.2%
   GEN. GEORGE G. MEADE SCHOOL	15.2%
   ANDREW HAMILTON SCHOOL	14.9%
   EDWARD T. STEEL SCHOOL	14.8%
   SAMUEL PENNYPACKER SCHOOL	14.4%
   JAMES RHOADS SCHOOL	14.2%
   WILLIAM C. LONGSTRETH SCHOOL	14.0%
   ROOSEVELT ELEMENTARY SCHOOL	13.1%
   MORTON MC MICHAEL SCHOOL	12.5%
   EDWARD GIDEON SCHOOL	12.3%
   WILLIAM DICK SCHOOL	11.6%
   EDWARD HESTON SCHOOL	11.5%
   ROBERT MORRIS SCHOOL	11.1%
   COOKE ELEMENTARY SCHOOL	10.5%
   DELAPLAINE MCDANIEL SCHOOL	9.4%
   DR. ETHEL ALLEN SCHOOL	8.4%
   RUDOLPH BLANKENBURG SCHOOL	7.3%
   RHODES ELEMENTARY SCHOOL	5.5%
   ROBERT E. LAMBERTON ELEMENTARY	2.7%

   Note: stored percentiles are computed by a batch script after loads; a difference from the live reconstruction means a newer load changed the comparison set and the batch has not been re-run.

   Evidence: metric tree: PSSA ELA proficiency (all tested grades)

3. 3
   The stored cellThe stored cell

   table

   philly_school_year_metrics

   value

   7.61

   denominator

   92

   suppressed

   false

   citywide_percentile

   0.0355

   comparison_group_percentile

   0.0750

   source_load_id

   bba25088-d2c0-415a-b47e-c47d1dcb2edc

   Evidence: data model overview

4. 4
   The load that wrote itWritten on 2026-06-03 by sdp_pssa_keystone.ts

   source id

   sdp_pssa_keystone_2024-25

   file URL

   https://cdn.philasd.org/offices/performance/Open_Data/School_Performance/PSSA_Keystone/2024_2025_PSSA_Keystone_All_Data.zip

   SHA-256 of the file read

   d040e16c1b88f33dd481efbdb1a3924951ab7cc81869c8dee52458280574c13aCopy hash

   bytes

   705,262

   year covered

   2024-25

   code commit

   63ddc08c2a63170cecb6e78b991559cef9aa3926

   To confirm you have the same file: download it from the URL above, then run shasum -a 256 <downloaded file> Copy command — the output should equal the hash above. If the publisher has since replaced the file, the hashes will differ, which is itself useful to know.

   Evidence: loader script · first-fetch findings for this file · source registry

5. 5
   The publisher's filePSSA & Keystone results, 2024-25

   School District of Philadelphia (Performance Office). State test results by school, test, subject, grade, and subgroup: counts and shares at each performance level, in two population cuts — the accountability cohort (students enrolled for the full year) and all tested students.

   format

   ZIP of CSVs (accountability-cohort and all-tested cuts)

   join key

   id_eos (= ULCS Code)

   landing page

   https://opendataphilly.org/datasets/sdp-pssa-keystone-performance/

   • Two cuts of the same results; the accountability cohort is the canonical one served by default.
   • District-run and alternative schools only; charter results come from the state's Future Ready file.
6. 6
   How it was checkedChecks: 2 passed, 2 flagged

   • ✓ passedBase case: served cells vs an independent re-read of the ingested file
   • ✓ passedCompleteness: every source cell is served
   • ⚠ flaggedAccountability-cohort vs all-tested files are byte-identical after sorting in SDP's 2024-25 archive — a publisher defect, so this check cannot distinguish the two populations
   • ⚠ flaggedCross-publisher sanity check vs the state's Keystone results

   Checked at ±1: 0 mismatches, 0 cells served but absent from the file, 0 in the file but not served (ALL, acct, latest year).

   Evidence: Base case · Completeness · Accountability-cohort vs all-tested files are byte-identical after sorting in SDP's 2024-25 archive — a publisher defect, so this check cannot distinguish the two populations · Cross-publisher sanity check vs the state's Keystone results

7. 7
   Assumptions & caveatsAssumptions and caveats

   • The accountability cohort (students enrolled for the full year) is the intended canonical population. However, the two files SDP publishes for 2024-25 ('Acct' and 'Actual') are identical once sorted — 28,525 rows with no differing value or denominator — so the served 'acct' and 'actual' cuts carry the same numbers. We treat this as a publisher defect (one file published under two names) and cannot say which population the numbers describe.

   • District-run and alternative schools only from this file; charter schools' Keystone results come from the state's Future Ready file.

   Algorithms involved: Citywide and peer-group percentiles, Peer groups: 40 nearest neighbors on demographics