Why Google analytics stats and Sitegainer stats don’t always match.

Google analytics is session-based, which means that when a user converts multiple times in more than one session, each conversion will be counted separately. Sitegainer is based on unique users, which means if a user converts multiple times in different sessions, there will be only one unique conversion registered, regardless of the number of sessions required to convert. Therefore, Google analytics measures conversions per session and Sitegainer measures conversions per user.