Hi Steve,
The SaleHoo Research Lab's 'sell through rate' is the number of listings that ended in a sale vs the number that didn't sell from the previous month on eBay.
Please note that the data updates every 7th day of the month.
You might find this article helpful - Link hidden: Login to view
Should you have other concerns about the SaleHoo Research Lab please feel free to let us know.
Cheers!