Finance, investing & gambling have a long & intertwined history.
Probability theory is said to have originated at the roulette table, and today use of odds is done by: the IRs in Singapore, Rubin when doing his merger arbritrage, Thorpe who first publicized how to beat blackjack almost came up with the Black-Scholes Theory and started one of the first hedge funds, Jain at Berkshire who figures out how to price insurance for earthquakes and takes odds for soccer matches.
So the original idea of value investing is find situations where the odds of success are high, like Graham's net-nets - if a firm is valued below working capital, a buyer should do well. And the more recent studies that show cheap PS PB outperforming the market over a time horizon. Then of course people now look at yields, NAV, ROE etc etc - take your pick.
Munger puts it very well here:
Any damn fool can see that a horse carrying a light weight with a wonderful win rate and a good post position etc., etc. is way more likely to win than a horse with a terrible record and extra weight and so on and so on. But if you look at the odds, the bad horse pays 100 to 1, whereas the good horse pays 3 to 2. Then it's not clear which is statistically the best bet using the mathematics of Fermat and Pascal. The prices have changed in such a way that it's very hard to beat the system.
And then the track is taking 17% off the top. So not only do you have to outwit all the other betters, but you've got to outwit them by such a big margin that on average, you can afford to take 17% of your gross bets off the top and give it to the house before the rest of your money can be put to work.
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The stock market is the same way—except that the house handle is so much lower. If you take transaction costs—the spread between the bid and the ask plus the commissions—and if you don't trade too actively, you're talking about fairly low transaction costs. So that with enough fanaticism and enough discipline, some of the shrewd people are going to get way better results than average in the nature of things.
http://ycombinator.com/munger.html