People are, by and large, quite poor at judging correct absolute values but are astute about determining relative values. Psychologists call this coherent arbitrariness, which suggests that individuals are coherent when they compare prices on a relative basis but arbitrary when those prices are considered versus fundamental value.
Michael MauboussinOnlookers frequently confuse edge with style...Edge means generating excess returns because of mispricing. Style suggests being in the right place at the right time. Sometimes edge and style overlap, sometimes they don't.
Michael MauboussinHumans have a strong desire to be part of a group. That desire makes us susceptible to fads, fashions, and idea contagions.
Michael MauboussinEdge also implies what Ben Graham....called a margin of safety. You have a margin of safety when you buy an asset at a price that is substantially less than its value. As Graham noted, the margin of safety 'is available for absorbing the effect of miscalculations or worse than average luck.' ...Graham expands, "The margin of safety is always dependent on the price paid. It will be large at one price, small at some higher price, nonexistent at some still higher price."
Michael MauboussinA thoughtful investment process contemplates both probability and payoffs and carefully considers where the consensus - as revealed by a price - may be wrong. Even though there are also some important features that make investing different than, say, a casino or the track, the basic idea is the same: you want the positive expected value on your side
Michael Mauboussin