Knowing the rate of your turnover is just half the story.  Combine this information with why and you have a useful collection of information to help reduce the costly bleed of knowledge and replacement costs.

Your reasons can be broken into 2 categories.  The first is prepopulatd with Involuntary, Voluntary and unknown.  The 2nd can be used to capture your choice of common reasons for leaving your employment, some good examples being New job, Health reasons and Competency Issues.  There is also a free text area to collect more information if needed.  These reasons are managed by going to Admin > Settings > Lookup Tables > User > Reasons for leaving and Reasons for leaving detail respectively.

Now when you make an employee a leaver by going to People > Employee name > Person (dropdown) > Remove you will also be able to capture the reason why they have left.

The Starter/Leaver report in Reports > People > People (dropdown) > Starters/Leavers let you examine this information is detail.