What we measure, and what we estimate.
The measured column comes from the marketplace. The estimated column comes from a named method: a review rate for units, supply by basket for sale value, and snapshot change for growth. We do not mix the two columns.
Measured — read from the marketplace
- Category tree (names, IDs, structure)all 11
We read the category structure from each marketplace.
- Catalog and listing counts10 of 11
We read the counts from each browse page.
- Listed price, lowest ask, discount10 of 11
We read the price from each listing and product page.
- Units sold, average sale price, transactionsTCGplayer
The marketplace publishes these records each day and each week.
- Seller lifetime unitsWhatnot
We read the lifetime unit count from each public seller page.
- Seller monthly value, orders, viewersWhatnot (on login)
The seller schema shows these fields. A partner login opens them.
- Cumulative review countall 11
We read the review count from each listing. It records past demand.
- Dated reviews7 of 11
We read the date on each review, and we use it for review speed.
- Interest signals (likes, shares, offers)Poshmark, eBay, Discogs
We read these counts. They show interest, not a sale.
- Demand badges (100+ bought, N+ sold)eBay, Walmart
We read the badge. It gives a band, not an exact number.
Estimated — from a named method
- Units sold per period, per categoryoutside TCGplayer
New reviews divided by a review rate of 2 to 4 percent. We calibrate the rate against client sales.
- Category sale valueoutside TCGplayer
Supply count multiplied by an estimated average order value. Or units multiplied by price.
- Category growth rateoutside TCGplayer
The change between snapshots over four weeks or more. We do not add past history.
- Sell-through and conversionall
Units sold divided by active supply, where the units are an estimate.