In Stage 1 you can include and exclude papers based on key concepts. You can search for concepts, or choose words from existing concept lists:

• Highly ranked words are concepts that are important and bear a lot of meaning, and they appear in many of the documents in your Focus study corpus. 
• Rare words are also meaningful but appear only occasionally in the documents. This means that selecting concepts from this category will usually include/exclude only a small amount of papers.