DentaIndexTransparency
How we calculate
A rating nobody can audit is just an opinion. This page is the whole method.
The composite score
Each review is scored across six things patients can genuinely observe, then weighted by the strength of its proof, how recent it is, the author's contribution history, and how specific it is. The weighted result is pulled toward the city average so that a handful of reviews cannot produce an extreme score.
| Sub-score | Weight |
|---|---|
| Result & durability | 0.25 |
| Price honesty | 0.2 |
| Pain & care | 0.15 |
| Communication | 0.15 |
| Hygiene & facility | 0.15 |
| Waiting & punctuality | 0.1 |
Every constant
These values are read from the scoring code each time the page loads. If one changes there, it changes here.
| A Receipt, fiscal cheque or contract | 1 |
| B Bank or card statement line | 1 |
| D Clinic-confirmed booking | 1 |
| C Treatment plan, prescription or appointment card | 0.8 |
| E Photographs with a coherent account | 0.5 |
| Review recency half-life | 18 months |
| Author trust multiplier | 0.5 to 1.2 |
| Detail multiplier | 0.8 to 1.1 |
| Shrinkage strength, clinics | 12 weighted reviews |
| Shrinkage strength, doctors | 18 weighted reviews |
| City average used when a city has fewer than 20 scored clinics | 7 |
| Weighted reviews needed before a score is shown | 5 |
| Penalty per upheld complaint | 0.4 points, capped at 3, fading over 24 months |
| Penalty: no price list published | 0.2 points |
| Penalty: verification refused | 0.3 points |
| Verification bonus, maximum | 0.3 points |
| Transparency bonus, maximum | 0.2 points |
| A month-over-month move larger than this is held for a person to check before it is published | 1.5 points |
| Reviews in one week that pause scoring: more than this multiple of the trailing rate, and at least the minimum count | 3 times, at least 5 |
| Verified reports needed to publish a price | 5 |
| Age after which a price leaves the current index | 18 months |
| Price recency half-life | 18 months |
| Outliers excluded from the median beyond | 3 times the interquartile range |
| Bands in each price spread chart | 20 |
The price index
We publish medians and percentiles, never averages: dental prices are right-skewed and a single expensive implant would distort a mean. A cell is published only when at least 5 verified reports back it; below that we say so and show the parent geography instead.
Illustrative. A score is never shown below 5 weighted reviews.
Check the working
Every figure on this site can be checked. Here are the rules, the method, and our mistakes.