Inconsistent results with multiple refiners

Question

I'm seeing some weird stuff going on with refining search results in SharePoint Online.

I've got a search results webpart set-up which returns items of a specific content type. Alongside it is a refiner web part which refines the results based on a managed metadata field set on those items. In this case, the refiner values are countries. There is no search box on the page as I just want it to show everything and let the users refine based on what they are looking for (requirement by the customer).

When refining, the following happens:

• Selecting "Netherlands" returns 9 results.
• Selecting "Belgium" returns 8 (different!) results.
• Selecting both Netherlands and Belgium returns 10 results, the 8 Belgium ones and 2 from Netherlands.

So search now 'lost' 7 results tagged with Netherlands. Why?

With a different combination:

• Selecting 'Algeria' returns 3 results.

• Selecting 'Netherlands' and 'Algeria' returns 11 results, 8 tagged with Netherlands and the 3 from Algeria.

• Selecting 'Belgium' and 'Algeria' returns 11 results, the correct ones!

I have trouble explaining (and fixing) this. In my opinion, selecting multiple refiners would result in an OR-type query, returning all results tagges with either of the values. By the way, all of the items are tagged with a single value, so they always belong to a single country. If this was an AND query, it should return nothing at all.

Answer 1

Could very well be a problem related to "TrimDuplicates". This functionality is activated by default and tries to remove duplicate items from your search results.

You can turn it off by editing the query with the query builder, going to Settings and turning off duplicate trimming, as per your comment :)