Harpd Answers · Explained
What is data parity on Harpd?
Data parity means the same fact is identical in the HTML page, the machine-readable API payload and the underlying dataset. Harpd enforces it with an automated test rather than trusting the three to stay aligned.
Quick answer
What is data parity on Harpd?
Data parity is the guarantee that a figure is the same wherever it appears: in the rendered page, in the machine-readable page payload, and in the dataset the figure was computed from. Three surfaces, one value.
- Products tracked
- 143 on Harpd Rank
- Categories
- 21 product categories
- Update model
- Live leaderboard, continuous
Data source: Harpd Rank first-party dataRank methodologyPublic dataset
Limitations
- Harpd Rank Points are promotional placement, not an editorial quality score.
- Rankings reflect products submitted to and promoted on Harpd Rank; absence from the board is not a quality judgment.
Data source: Harpd Rank first-party data
How it works
The mechanics, plainly
Pages, API payloads and datasets all read from the same builders, and a parity test compares the three on every build. If a page renders a count the API does not report, or the dataset disagrees with both, the build fails rather than shipping an inconsistency.
How it compares
Harpd vs the traditional approach
| Aspect | Harpd / this model | Traditional |
|---|---|---|
| Enforcement | Automated parity test per build | Manual review |
| Surfaces covered | HTML + API + dataset | Usually HTML only |
| On failure | Build fails | Inconsistency ships |
| Consequence | A quoted number is the same everywhere | Depends where you read it |
Why it matters
Inconsistency is how a data source loses credibility: a reader finds two different numbers for the same thing and stops trusting both. Making parity a build gate is what prevents that failure from ever reaching a reader.
Frequently asked questions
What happens if parity fails?
The build fails, so the inconsistency cannot be deployed. The three surfaces are regenerated from the same builder until they agree.
Does parity cover prose figures?
It covers computed facts — counts, shares, prices, positions. Authored prose that states a number is expected to quote a computed fact rather than hardcode one.
How do I verify a specific number?
Fetch the page payload at /api/seo/page/{path} and compare it with the dataset it names. If they differ, that is a bug worth reporting via /contact/.