We are using firebase analytics in our iOS app.
I would like to find out number of new active users in a month and the attrition of our app monthly i.e., the number of users leaving the app every month.
Attrition for a month(suppose January) can be calculated as
attrition = (monthly active users of January) - (monthly active users of January and February)
where (monthly active users of January and February) is the no of users that are active in January and also active in February.
Example: There are 100 monthly active users in January and 120 in February. The difference 20 can be interpreted either as 20 new users or as 40 new users and 20 left the app.
In the latter case the attrition can be calculated as
active users of January and February = 80 (20 left the app in January and rest of the users are still active in February)
attrition = monthly active users of January - active users of January and February
= 100 - 80 = 20(the number of users who left the app)
The firebase console shows the number of monthly, weekly and daily active users. But it doesn't let us filter users who are active in 2 different months.
So how to find the attrition and new active user count of our iOS app using firebase?