In the User Insights Retention analysis, it is possible to observe retention rates higher than 100% when analysing a level 2 site.
In this case, the reference volumes correspond to the visitors who visited the level 2 site analysed (column 2).
To calculate the retention rates, the reference population is extended to the perimeter of the level 1 site. Therefore, the calculation is:
Retention rate = Visitors on level 2 who visited level 1 during the reference period / Visitors on level 2 during the reference period
A large increase in traffic on a level 2 site specifically can therefore lead to retention rates over 100%.