Method
How a score
becomes a measurement.
The instrument
LabTest IQ administers thirty items spread evenly across four reasoning domains: pattern recognition, numerical reasoning, verbal analogy, and spatial transformation. Each item is hand-authored and reviewed; difficulty is set on a three-tier scale calibrated against established cognitive psychometrics.
Scoring
Each correct answer contributes points equal to its difficulty tier (1, 2, or 3). The raw total is mapped to the canonical IQ scale — mean 100, standard deviation 15 — using a piecewise-linear function anchored at the bank's theoretical maximum. The mapping is published in source.
Percentile
Your percentile is computed as the standard normal cumulative distribution function evaluated at your z-score. Specifically, percentile = Φ((IQ − 100) / 15) × 100. We use the Abramowitz & Stegun (1965) erf approximation 7.1.26, which is accurate to 1.5 × 10⁻⁷.
Bands
Bands are conventional ranges used in clinical reporting: Average (85–115), Above Average (115–130), High (130–140), Very High (140–150), Exceptional (≥ 150). They are informative summaries, not diagnostic categories.
What this is not
LabTest IQ is a self-administered screening instrument. It is not a clinical assessment. Diagnostic intelligence testing requires individualised administration by a licensed psychologist using validated, copyrighted instruments such as the WAIS-IV.
Privacy
Your attempts and training sessions are persisted only in your browser's local storage. No identifiers, scores, or events are transmitted to any server. Clearing your browser data permanently deletes your history.