The stars next to a Record Match are a “confidence score” for each match. They are based on the degree of similarity of the information in the record (names, dates, facts, relationships, etc.) to the information in your family tree.
Record Matching is highly accurate, but its accuracy doesn’t come at the price of finding fewer matches (i.e. only the obvious ones). Record Matches assesses the likelihood of each match being relevant to a family tree individual, and in the process assigns a Confidence Score for each match based on the degree of similarity of the information in the record (names, dates, facts, relationships, etc.) to the information in the family tree.
We have prepared an additional sub-system which we codenamed "Devil's Advocate" which goes over the matches and reduces the score or completely rejects those that contradict information in your family tree, to reduce false positives to the minimum.
This Confidence Score, which is a unique feature of MyHeritage, is displayed next to each match and ranges from half a star to five stars.
You can sort matches by score on every page, or filter matches by the score and look only at higher probability matches, or extend the scope to look at all matches, likely and unlikely.
Please note: the higher the score, the less interesting the match might be! This is because a high-scoring match means that the historical record contains and matches a lot of information in the tree, hence your tree probably contains a great deal of information about this individual, so the new match may possibly not add much new information.
There may be 'genealogy gold' particularly in the lower scoring matches where the system is less confident about the relevancy of the match, but that doesn’t mean the match is less interesting or brings less information, rather there may not be much information in the family tree about this person to lift up the score.