outlines, information

I outlined the K+A environments paper.

I started to outline my talk for Marseille, but then got stuck on the question of whether or not to go postal on information and statistics. The issues are things like:

• Look at concentration as a function of environment or look at environment as a function of concentration? Since concentration is measured at much higher signal-to-noise than (our measures of) environment, the latter contains much more information, and is more constraining on models, even if you prefer to think about it the other way.
• Fit models to the color–magnitude diagram or fit models to the age–mass diagram? Since the ages and masses are derived from the colors and magnitudes, and because there are many uncontrolled parameters in going from color and magnitude to age and mass, it is almost always much more constraining to fit models to color and magnitude, even if it is age and mass that you really care about. Besides which, the age–mass relation contains much less information, in the sense of, say, the Cramer–Rao bound.

These points are simultaneously trivial, important, oft-ignored, and audience turn-offs.