How often do you review and validate your practices/process?

Question

We currently drive changes to our process through the following mechanisms:

• Weekly wrap-up meeting
• Project postmortem

We discuss what isn't working, what is working, etc. I use these settings to introduce new practices, and eliminate ones that aren't working. We usually only make 1 change at a time and try it for 2 weeks to a month.

To validate our change we look at:

• our velocity and std. deviation (work accomplished week over week)
• dialectic
• our opinion/perception of the practices effect and effectiveness

Those practices which seem to work for us we keep. Everything else is removed. This has worked pretty well for us, but I'm always interested in better ways to do this.

How often/When do you review you development process?

How do you validate the changes in your process are effective?