Practical Data How it works
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Read
Code extracts each table, resolves merged cells, and parses values:
$0.025,.312,6' 6",1.5B,20–25,2:59,≤ 272K. A2:41game length is a duration; a7:05start time is not. It computes the ranges and spreads, and describes them in words. -
Judge
A System One model (Jev) answers narrow, typed questions with probabilities:
- Is this column an amount, an identifier, a time, a rank, or a cutoff?
- Is a higher value better, worse, or neither?
- Do ratios matter more than differences (log scale)?
- Are these labels ordered grades? Which of two is the lower grade?
- Is this row a total? Do same-named columns in other tables share a scale?
- Are values compared down each column, or across each row?
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Paint
D3 maps each value onto a ColorBrewer scale and blends it over the page's own background. Every cell keeps WCAG AA text contrast, and the extension restores the page exactly when you turn it off.
- 165 / 165
- hand-labeled columns shaded or left plain correctly, across 21 test pages (a regression check, not an accuracy estimate)
- 81 / 81
- directions of "better" judged correctly
- ~$0.001
- typical cost to judge a page; repeat visits are free
Open source, top to bottom.
Practical Data is MIT-licensed. The extension, the questions it asks the model, the test pages and the recorded answers are all on GitHub.
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Read what you install
The store package is built unminified from the same repository, so the code running in your browser reads like the source.
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No server in the middle
Your key goes straight to the provider you pick. The author runs no backend and collects nothing: no analytics, no telemetry. Privacy policy
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Check the claims yourself
One command replays every recorded judgment offline: unit tests, the hand-labeled eval, and 21 pages in a real browser. No key needed.
$ git clone https://github.com/philrenaud/practical-data
$ cd practical-data && npm install
$ npx playwright install chromium
$ npm run checkView the source on GitHub Report a misread table How the questions are designed
Install
- Download the extension and unzip it.
- Open
chrome://extensionsand turn on Developer mode. - Select Load unpacked and choose the unzipped folder.
- On the options page, paste a TypeSafe API key and select Test. A typical page costs about a tenth of a cent; unchanged tables aren't judged twice.
The Chrome Web Store listing is coming soon. Until then, the extension loads unpacked.
Tables are judged as they scroll into view, up to 200 per page. Table text (headers, sample values, a few rows) is sent to the provider you choose to be judged; nothing is sent for sites you turn off. Your key stays in the extension's storage. The toolbar popup turns a page or a whole site off, and ⌥⇧H toggles the current page.