Book
Zen Jiu Jitsu: The 30 Day Program to Improve Your Jiu Jitsu Game 1000% (Volume 1)
Two parallel scores from 5 calibrated reviewers and 5 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. The 30-point gap is the rating-inflation signature for this title — discriminating reviewers liked it more than the casual crowd.
Where this book sits
Z-normalized percentile · 5,285 ranked books
| Mean reviewer z-score | +0.019 |
|---|---|
| Calibrated raw-mean rating | 4.20 /5 |
| Broad raw-mean rating | 4.20 /5 |
| 90% CI-floor (z) | -0.717 |
| Reviewers (calibrated / broad) | 5 / 5 |
Summary
Zen Jiu Jitsu: The 30 Day Program to Improve Your Jiu Jitsu Game 1000% (Volume 1) sits at the 40th 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 10; 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
5 reviewers with rating variance re-centered onto a personal z-scale.
Mean z = +0.019. Broad raw mean = 4.20/5.
90% CI-floor = -0.717. Thin samples penalized.
Global 40.1. Z-track and raw-track ranked separately.
Similar percentile
