Probabilistic and Approximate Variablesby Mohnish Pabrai
Usually two to three variables control most of the outcome. The rest is noise. If you can handicap how those key variables are approximately likely to play out, then you have a basis to do something. Things that are approximate and probabilistic don't lend themselves too well to Excel modeling. For me, if I find myself reaching for Excel, it is a very strong sign to take a pass. The thesis ought to be painfully simple in your head.
Tags: stock picking