This solution explains how the EmailFinder service matches records.
EmailFinder will match in the following order:
An individual match - Full name (First and Last) and address
A household match - Last name and address
If no matches were found, we were unable to match the name and address from the Constituent record in The Raiser's Edge with the database we use for EmailFinder. When a match is found the email address is verified as active to prevent bounceback emails from being returned in the results.