This is part 4 of a 5 part series on Advanced KPIs. One of the key challenges in mobile gaming is retaining users in a world where there are so many games competing for their attention. When engagement and retention are your critical challenges, you need a KPI that captures the essence of both. All games track the total number of unique users active everyday, known as Daily Active Users, and the total number of unique users active in a given month, known as Monthly Active Users, but alone neither capture the frequency of use or retention of users. To that end, many mobile gaming companies divide their average Daily Active Users (DAUs) by their Monthly Active Users (MAUs) to create a KPI called DAU/MAU.