Overview of Content Experiments
How conversion rate is calculated for experiments
Conversion rate is calculated using the same methodology as Analytics: total converted visits divided by total visits (once a user becomes a part of an experiment). A user is considered part of an experiment once he or she has seen the experiment page. For example, if a user sees the experiment page, then comes back the next day, the second visit is counted, even if the user does not view the experiment page again.
This counting methodology provides better consistency with other Analytics reports and, except for rare cases, does not change experiment winners determined from the previous methodology.
Note: Experiments started before 11/03/2014 use a different methodology that counts total converted visits divided by total experiment visits. This can produce inconsistencies in conversion rate metrics and result in conversion rates greater than 100 percent.