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River Cottage Gluten Free cover
global pct
5.7

Book

River Cottage Gluten Free

Two parallel scores from 3 calibrated reviewers and 3 raw-average reviewers.

5.7%
Z · Global
5.7%
Z · Cohort
6.4%
Raw · Global
6.4%
Raw · Cohort
Two scores · one item
Z-normalized · global
5.7
Z-normalized · cohortpublication decade
5.7
Raw average · global
6.4
Raw average · cohortpublication decade
6.4

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

0255075100

Z-normalized percentile · 5,285 ranked books

Mean reviewer z-score-0.942
Calibrated raw-mean rating4.00 /5
Broad raw-mean rating4.00 /5
90% CI-floor (z)-1.892
Reviewers (calibrated / broad)3 / 3

Summary

River Cottage Gluten Free sits at the 6th 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 6; 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

01
Z-score per reviewer

3 reviewers with rating variance re-centered onto a personal z-scale.

02
Aggregate

Mean z = -0.942. Broad raw mean = 4.00/5.

03
CI-floor

90% CI-floor = -1.892. Thin samples penalized.

04
ECDF percentile

Global 5.7. Z-track and raw-track ranked separately.

Similar percentile

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