Candidate ranking is what happens when you utilize a scoring system in your recruitment process. Each candidate receives a score based on how well they meet your defined criteria. Then you can rank candidates according to who is the closest match to what you are looking for.
Candidates who rank the highest after the round of reviews of the CVs and cover letters may be invited to interview. During the interview, you can score candidates based on their answers. These scores are added to the ones from the previous round to update the candidate ranking. This makes it easy to defend your recruitment decisions and compare candidates.