Book
National Geographic Readers: Level 2
Two parallel scores from 9 calibrated reviewers and 14 raw-average reviewers.
Z-normalized corrects for reviewer bias (every reviewer re-centered onto their personal scale). Raw average uses simple mean across the broader pool including stddev=0 reviewers.
Where this book sits
Z-normalized percentile · 5,285 ranked books
| Mean reviewer z-score | +0.198 |
|---|---|
| Calibrated raw-mean rating | 4.67 /5 |
| Broad raw-mean rating | 4.79 /5 |
| 90% CI-floor (z) | -0.351 |
| Reviewers (calibrated / broad) | 9 / 14 |
Summary
National Geographic Readers: Level 2 sits at the 56th z-normalized percentile across 5,285ranked books. The z-percentile differs from a raw star average because Rankquant subtracts each reviewer's personal baseline before aggregating — so a reader who rates everything 5 stars carries less weight than one who rates discerningly. Raw-average percentile is 45; the gap between the two measures how much bias-correction changes this title's standing. How percentiles are computed.
Pipeline applied to this title
The math, in this order
9 reviewers with rating variance re-centered onto a personal z-scale.
Mean z = +0.198. Broad raw mean = 4.79/5.
90% CI-floor = -0.351. Thin samples penalized.
Global 55.6. Z-track and raw-track ranked separately.
Similar percentile
