The reason mix report

Most churn reporting is a rate. A rate tells you the size of the problem and nothing about the problem.

The reason mix is the same population sorted by cause, tracked as proportions over time. Priced out. Went to a competitor. Never activated. Champion left. Business changed. No longer needed. Bad fit at sale.

Two things become visible that a rate hides. The first is that a stable churn rate can conceal a complete change in composition, and each cause has a different owner and a different remedy. The second is that the proportions move before the rate does, which makes the mix an earlier signal than the number it is drawn from.

The discipline that makes it work is fixed categories, assigned at exit by someone who spoke to the customer, with a mandatory single primary cause. Multi-select destroys the proportions. An "other" category above about ten percent means the categories are wrong and need revising, which is a finding rather than a failure.

The category to watch hardest is bad fit at sale, because it is the only one where the remedy sits entirely outside the function doing the reporting, which is exactly why it tends to be quietly reclassified as something else.