The RLD (or Rational Design Handbook) is a series of articles which looks at the various ways in which we can quantify elements of user experience and then use empirical data to drive our game design decision making processes. Although I have written about RLD before, I have never publicly released anything which looks at the concept from the ground up. The first part of the RLD handbook can be found here.
As this article has been up for a few months now, there are quite a few comments. It’s worth taking the time to go through these to see the reaction of the community. Raph Koster even took the time to discuss how tools don’t stifle creativity.