Filtering search results allows a user to narrow a search based on the selected filter criteria. For example, you can search for sources with the term "economic recovery" and then filter based on political affiliations to create bins for Republicans, Democrats, Independents, etc.
Alternatively, you can use Advanced Search to build a search that includes a filter. This is better if you know all the filters you want to use, but is less useful if you want to switch quickly between groups. This is because you would need to build a new advanced search instead of just ticking and un-ticking search criteria.
Note that when selecting multiple filters, the system only displays results that meet all of the filter criteria (i.e. it's joined by an AND, not an OR).
Click on a filter twice to exclude it from the search results.