We basically followed the idea of buying comapnies selling below working-capital - at two thirds of working-capital.
I agree with Warren to keep it simple and not use higher mathematics in your analysis.
I helped Ben with the third edition of Security Analysis, published in 1951.
Most look at earnings and earnings potential, well I can't get into that game.
I find it helpful to buy near the low of the last few years.
I'm a passive investor. There are people who are very aggressive; they try to buy companies.