Louis Bachelier's Random WalkSeveral tests of market efficiency have been developed over the years. The very first test, constructed by Louis Bachelier in 1900, measured the probability of a number of consecutively positive or consecutively negative price changes, or “runs.”
The randomness of runs is rejected with 95 percent statistical confidence whenever the plotted value is greater than 0. The randomness of runs cannot be rejected if it's < 0.
