whaleprep/DATA.md

Data sourcing — JEE Main question bank

Status

scripts/import_examgoal.py imports 9,813 real JEE Main PYQs (2002–2025, all three subjects) from the MIT-licensed jee_mains_pyqs_data_base release asset (1762787474-DataBaseChapters-v007.pkl, ~24 MB, 14,973 questions total). The keep rule is: type=mcq, fully text (no <img> anywhere in stem/options/explanation), exactly one correct option in A–D. Skipped: 1,909 image-questions, 2,875 answer-less, 19 multi-correct, ~357 with stray images in options/explanations.

python3 scripts/import_examgoal.py path/to/app.db [--pkl db.pkl]

Safe to re-run: INSERTs skip stems already present, so the 24 hand-written seed questions are never duplicated. Existing deployments pick up the new CREATE INDEX statements on boot (init_db runs them idempotently).

The demo seed (src/db.rs, 24 hand-written questions) remains as the offline fallback when the pickle cannot be fetched. scripts/expand_seed.py is kept for synthetic load testing only.

Attribution

Question content: HostServer001/jee_mains_pyqs_data_base (MIT), itself reverse-engineered from a subscription site's API and cached. Upstream model credit: examgoal database schema. No NTA PDFs were scraped — NTA publishes image-rendered PDFs with no machine-readable question text (pdftotext yields only question IDs).

Schema mapping

The bank is organized into the official NTA JEE Main syllabus units (2026 Paper 1 B.E./B.Tech):

• Physics: 20 units (Units and Measurements through Electronic Devices)
• Chemistry: 21 units (Some Basic Concepts through Practical Chemistry)
• Maths: 14 units (Sets, Relations and Functions through Trigonometry)

scripts/reorg_nta_units.py maps upstream subtopics into these units by keyword matching; stragglers are placed manually (documented in the script).

The 24 hand-written demo questions that previously shipped inside the seed have been removed from the live bank: they were trivial one-liners that diluted difficulty. A fresh install still seeds them so the app is not empty before import (see src/db.rs), but they are labeled in the seed code as demo content.

Sanitizer contract (both sides match)

Write side (import_examgoal.py::sanitize) and read side (views.rs::rich) share one allowlist: br p sup sub b strong i em u ol ul li table tbody thead tr th td span h3, attributes always stripped, <picture>/<source>/<style>/<col> blocks dropped whole. KaTeX renders $$..$$ display math and \(..\) inline at page load with trust: false.

Adding more questions later

Re-run the importer against a newer pickle release. For NUM questions the upstream data carries no answers, so they are excluded until a verified answer source exists. The answer column for MCQ is a single letter.

Why NUM answers are not extracted from explanations

Audited 2026-10-12: integer-question explanations do end with the numeric result (= 80, Total 11, is 8), but the phrasing varies per question (Hence, Clearly, no. of integers in S is, bare = X mid-derivation) and several tails contain multiple numbers. A regex would mis-key a meaningful fraction, and a wrong answer key teaches the wrong result — worse than no question. NUM import stays out until NTA final answer keys (authoritative per-shift source) are transcribed. The grader already supports NUM with 0.1% tolerance for hand-added questions.

Better-database search (2026-10-15 findings)

Verdict: our current source (HostServer001 examgoal-derived, 9,813 questions) remains the best publicly usable structured JEE Main bank.

Repositories audited:

1. thesrijankumar/Indian_Exams_PYQ (GitHub, ~4 MB) — contains 223 JEE Main shift-wise PDFs (2020-2026) plus JEE Advanced. Sounds ideal, but:

   • All files are stored in Git LFS, and the LFS batch API returns no download URLs (free-tier bandwidth cap) — files are effectively inaccessible without authentication.
   • Even with access, they are scanned PDFs: NTA renders question text as images, so pdftotext yields only question IDs (verified earlier on NTA's own cdnbbsr PDFs). No text-layer exists to extract.
   • Use: a future per-shift "actual paper" mode could render these PDFs page-by-page as images, but not as structured questions.

2. examgoal CDN images — the 1,909 image-questions we skip at import reference app-content.cdn.examgoal.net / imagex.cdn.examgoal.net URLs. All return 403/404 without signed URLs. Hotlinking is a dead end; embedding them would also break whenever their CDN expires.

3. jiteshtripathimath-lab / SBStudio07 / aryan-kronos — marketing sites and Telegram bots, no structured data.

Why "Hard mode feels easy" (resolved):

• The 24 hand-written seed questions (Q1-Q24) were trivial one-liners mixed into the real bank. They are now deleted from the live DB.
• The difficulty labels come from the examgoal source's user-vote metadata, not from NTA. Distribution across 9,789 real PYQs: 4,007 Easy / 5,614 Medium / 168 Hard. JEE Main genuinely has few "hard" questions per shift (~2-3 of 75); the exam's difficulty comes from time pressure, not per-question complexity. For a harder practice set, filter to Medium+Hard and recent years (2021+) — the builder supports both filters now.
• All 9,813 questions verified exam='jee-main' in source metadata (2002-2025, AIEEE-era questions included since AIEEE IS JEE Main's predecessor under the same NTA syllabus).