Methodology

1. Spaced repetition for vocabulary and missed questions, using the SM-2 algorithm (the basis of Anki). Reviews due at 1, 3, 7, 14, 30+ days based on rating.
2. Interleaved practice in the Daily Challenge: 10 questions mixed across all four PreACT 9 sections. Research shows interleaving yields ~77% retention vs. ~38% for blocked practice at 24 hours.
3. Mandatory error analysis: every wrong answer is categorized (didn't know concept, misread, ran out of time, arithmetic slip, wrong strategy, guessed). Pattern visualization shows the dominant mistake type.
4. IRT-lite mastery scoring: easy/medium/hard questions weighted 1.0/1.5/2.5. A topic isn't mastered until the student handles hard questions reliably.
5. Realistic mock conditions: four sections (English, Math, Reading, Science) with per-section timers totaling ~2.5 hours, navigation panel, flag-for-review, auto-submit on timeout — matching the PreACT 9 Secure (which allows a calculator in Math only).

The choices above are not invented; they come from cognitive science literature on retention and skill acquisition. Selected references:

• SuperMemo SM-2 algorithm (Wozniak, 1990) — the basis of every modern spaced-repetition system.
• Rohrer & Taylor (2007) on interleaved practice in mathematics.
• Roediger & Karpicke (2006) on the testing effect (retrieval practice).
• Item Response Theory (Lord, 1980) for difficulty-weighted scoring.
• Self-Determination Theory (Ryan & Deci, 2000) for our streak/freeze mechanic and mastery-tied (not vanity) achievements.

CPS does not publish official HSAT items, and we do not have access to retired test items. Our practice questions are:

• Original CC0 questions written to mirror HSAT structure and difficulty.
• Adapted from public-domain state assessments aligned to the same 8th-grade Common Core standards: NYSED Grade 8 ELA & Math, Massachusetts MCAS, Illinois IAR, Smarter Balanced.

Each question carries a source and license field visible in the explanation. We claim our practice mirrors the real test in format and difficulty distribution; we do not claim it shares actual content.

• We do not use leaked or retired HSAT items. There aren't any publicly available; if there were, using them would be unethical.
• We do not use shallow gamification (XP bars, badges for opening the app). 8th-graders see through that.
• We do not claim a guaranteed score. Score depends on practice consistency, baseline ability, and test-day variance.
• We do not collect any personal data on the server. The only measurement is an anonymous, cookieless page-view count on analytics we host ourselves (see the Privacy page) — never anything about an individual student or their answers.
• We do not advertise. There are no third-party scripts in the app — Lighthouse confirms zero trackers.

The CPS test is now the PreACT 9 Secure, scored on the ACT scale. The score report shows:

• Each section (English, Math, Reading, Science) on a 1–32 scale — an estimate from your raw score, based on the raw-to-scale ranges in ACT’s published PreACT 9 practice-test scoring guide (we show the midpoint of the range).
• A composite that averages the four section scores (also 1–32).
• Your admissions test points (composite × 10, max 320) and, if you enter grades, your 7th-grade grade points (GPA × 80, max 320) — the two halves of CPS’s 640-point total.

We deliberately do NOT show a PreACT cutoff: CPS will not publish cutoffs on the 640-point scale until after February 2027 results, and the historical 900-point cutoffs cannot be converted. Everything we show is labeled as an estimate, not a guarantee.

If you spot a question with an incorrect answer or explanation, or if CPS publishes new information about the HSAT format, please email hello@chicagohsat.com. We update the question bank in batches; bug fixes ship within a few days when reported.