> The best "matching" shirts are then likely blue But this means there are then non-blue shirts. One of the issues for us is that we wanted to rank by item su

> The best "matching" shirts are then likely blue But this means there are then non-blue shirts. One of the issues for us is that we wanted to rank by item suitability for the user, not by relevance. When using FTS, this didn't work because you'd get a non-blue shirt that would be better for the user and that showed up first. But when using the filter-based search, that couldn't happen because the recommendation algorithm was only getting blue shirts to rank, so all of them were relevant, and the same level of relevance.