About
A project to make VCE statistics accessible, transparent, and useful for students.
What data is available
Why this exists
This project started as a personal tool to help me make decisions about my own studies, and eventually grew into the platform you see today.
- VCAA reports are difficult to use. The honour roll is the best example. All the data is sorted and accessible in one place, including the actual number of high achievers — sites like quppa.net don't count students without consent for name release.
- Accurate scaling data is scarce. The VTAC scaling report rounds scaled scores to 0dp when they use 2dp internally, and all online ATAR calculators do the same.
- Existing calculators lack transparency. I wanted to know exactly how estimates were calculated, which existing tools don't reveal.
How scaling data is calculated
The Mathematical Model
VTAC doesn't publish a formula or exact scaled scores. Instead, they provide rounded anchor points for raw scores of 20, 25, 30, 35, 40, 45, and 50.
1. PCHIP Interpolation
For raw scores below 20, Piecewise Cubic Hermite Interpolating Polynomials model the lower range.
2. Constrained Cubic Regression
For scores ≥ 20, a weighted cubic is fitted to the official anchors plus validated crowdsourced points, with P(20) and P(50) pinned exactly and a non-negative derivative enforced across the range (strict monotonicity).
3. Crowdsourced Validation
Crowdsourced (raw, scaled) pairs are checked against a quadratic baseline fitted to the official anchors alone. Any point deviating more than 0.45 scaled points is rejected. Anchor points near a crowdsourced value are down-weighted so the crowdsourced data wins where the two overlap.
Accuracy Disclaimer
Scaling graphs are statistical approximations. They may be slightly inaccurate for specific scores due to curve fitting and the lack of official data. Use the Calculated line as an estimate, not a guarantee.
For the ATAR calculator, exact points are used when possible over calculated values, including scaled 50.00 and crowdsourced data points.
The Distribution Graph
Study Score Distribution graphs are reconstructed visualizations. VCAA publishes the exact number of students at each study score from 40 to 50, but nothing below 40. The remaining cohort is filled in from a Gaussian (mean 30, standard deviation 7), which is how study scores are designed to be distributed.
The cohort size comes from exact enrolment data where available (2025); otherwise it is estimated from the 40+ tail. For small cohorts where data is not published (<5 students) the graph falls back to a reference distribution instead.
Note: These graphs are illustrative only. They help relate your score to the state, but should not be used to determine exact rank.