If you do a filter search in Marketplace for jobs/candidates/members and are getting inaccurate results, read on...
When you input several layers of fields to search on, it can get tricky using the AND / OR qualifiers in between. What the search does is it groups the AND's together first, and separates them from the OR's.
So if you are looking for a attorney/lawyer who does tax in PA, and group it like this, you will get inaccurate results:

This will give you results you don't want (Attorney candidates in other states), because it is grouping the AND's together first. So that search is actually searching for (Attorney - in any state/country) OR (Lawyer + Tax + PA).
You would have to set it up like this:
Job Title includes Attorney
AND
Job Title includes Tax
AND
State equals PA
OR
Job Title includes Lawyer
AND
Job Title includes Tax
AND
State equals PA
If you are doing a search for something specific like this, I suggest trying the keyword search (top right hand search bar) and doing a Boolean search instead:

Lastly, with any search method, the more fields you add, the less results you will get. I use filter searches for broad searches like "Industry = Construction" and "Country = US", or something like "Occupational Category = Information Technology". I use the keyword search for more specific searches like "Optics" or a Boolean string like "TS/SCI" OR "cleared" OR "DoD".