The ability to run multiple scenarios of future and past data sets simultaneously. It is very user-friendly and intuitive. I can't think of anything that would be improved or changed in the software. I have used it for many years now, but my first use was only about 10 years ago. I've also used other tree age software as well as excel spreadsheets. This is by far the most intuitive, easy to use solution I've ever encountered. A must try for anyone looking for a robust tool to analyze their medical data. We are able to do comparative analysis between different populations with our insurance database.