One must be entirely sensitive to the structure of the material that one is handling. One must yield to it in tiny details of execution, perhaps the handling of the surface or grain, and one must master it as a whole. ↗
One important measurement issue concerns the fat tails problem that I mentioned earlier. VAR is concerned with extreme outcomes. If the tails of the probability distributions we are using are too thin, our VAR measures are likely to be too low. ↗