The Phillips DNA Project News

Does testing more markers improve the quality of matches?

You should test more Y-chromosome DNA short tandem repeat (STR) markers when you wish to compare additional markers against others with similar results. They will refine your matches for genealogical purposes.

It does not increase the number of generations traced by a Y-DNA STR test but rather reduces the range of generations in the time to a common ancestor with your match. It also does not generally increase your number of matches.

If you do not have many matches or do not have many matches that have tested more markers, you may still choose to upgrade. That way as the database grows and you gain additional matches, you will be prepared to make comparisons that are more refined. 

Phillips DNA Blog