What is "decision theory"?

[Mentat]

The title says it all. I don't have any knowledge whatsoever on the matter, and just want to know what it is.

Any information is appreciated. [:)]

[selfAdjoint]

Here's a brief reference (http://pespmc1.vub.ac.be/ASC/DECISI_THEOR.html); it's not so much a theory as a collection of techniques to analyze information in the presence of confusing factors. Part of operation research or managment science.