Having the ability to continuously measure your business is essential to measuring any change (whether you have a new policy, big new customer, or shiny new tool from Orlando). You need to be able to measure and report in an ongoing way.
Compare Time Periods
What were your metrics for the trailing 12 months before you bought the tool? How does that compare since then?
Once you can continuously measure your business, you should be able to look historically and analyze trends. (“Since I implemented this tool, how has my helpdesk improved?”)