User churn is a common phenomenon in online communities. In order for the community to continue to exist, it is necessary to compensate for leaving users with new ones.
The difficulty in creating this metric comes down to defining a churned or inactive user because it varies greatly from community to community. A good starting point would be to consider a user to be inactive if they have not performed any action during the quarter. On the other hand, when you count the influx of new users, don’t forget to count the reactivated ones.
Depending on what you care about, you can present the metric as a ratio or as a difference.
- The ratio allows one to see the proportion of new users to those who became inactive. If the ratio is greater than one, then there are more users who join and the community can be considered healthy. If the ratio is less than one, then the user churn is greater than the influx of new ones, and this situation is not good.
- The difference allows one to look at the absolute number of the user balance that sometimes is useful.
This is a fragment of a draft of the book “Lessons Learned While Working On Stack Overflow”. Read the full book on kindle or the paperback version.
I have a dedicated tool that calculates user churn. Here is more information on the topic.