How do Mixpanel analytics cohorts really work

Did you know that when you use Mixpanel cohorts to analyze trends month by month, the way Mixpanel calculate user numbers per month in most cases will result in having the same user with the same event counted in two different months? 🤯

To illustrate this let's take a basic example of a cohort “Users who sent a message for the first time ever in the last 30 days”.

The way Mixpanel plots this cohort month over month works like this:

1. Mixpanel checks each date for each month to see which users qualify for the cohort (i.e., which users did the event in the last 30 days on the first day of the month, the second day and so on).
2. This process repeats for each day in the month for every month in the report

Knowing this, let’s consider a user who shared their first post on June 10th.

This user qualifies for both the June and July cohorts because, if you look back from, say, July 5th, they did perform the event in the last 30 days.

As a result, this single user for their single event is counted in both the June and July cohorts.

Read the full article here: https://futureproductlabs.com/how-mixpanels-cohorts-work/