What are KPIs, statistical metrics and metrics in general for you?
Do you distinguish them?
I think that the difference between Metric and KPI is pretty much a matter of semantics and you can define them however you want. Having said that, when I taught the Practitioner courses, I used this example:
If you were to draw a graph with the values you were measuring on the Y axis and Time on the X axis, then a single point on that graph would be a Metric. In fact, any individual point on the graph is a Metric.
But if you then take multiple metrics and drew a line between them, you would have a Key Performance Indicator.
Mind you, the line is not the Key Performance Indicator, it is the Angle of line and its relationship to the Time axis that determines the Key Performance Indicator (e.g.; A 10% improvement in the month of Dec. A 20% decrease over last week).
I would then cover the fact that the reason you have Key Performance Indicators is that you are trying to reach a Critical Success Factor (CSF). Measuring the difference between points does very little if you haven’t set a goal. The goal is the Critical Success Factor.