Relevancy:

When searching for people in Muck Rack, your results will default to Relevancy. This shows journalists most relevant to your search terms and criteria. Relevancy means that your terms match keywords in journalists' bio details or appear in journalists' tweets and/or bylined articles the most. Any search you run in Muck Rack will default to including the past 25 months of coverage from today's date (as that's the furthest back you can pull) unless you apply a date range filter.

Recency:

Shows journalists that have mentioned your search terms most recently in their articles or tweets. This is helpful for monitoring recent coverage and learning about which journalists are writing about specific topics now.

Outlet Rank:

Shows journalists based on your search terms that work for top-tier publications first.
For example, journalists who work for publications with the highest UVMs (unique visitors per month) will be placed at the top of your search. 

Here's a guide on search best practices to help refine and target your results.