Several 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....
Random Walk Index indicator script. This indicator was originally developed by Michael Poulos.
As you can see, the result is very similar to the Vortex Indicator (was developed by Etienne Botes and Douglas Siepman).