DMI trading rules
by Jim Summers, Ph.D.
In this issue, we start programming into Lotus 1-2-3 the trading rules used in J. Welles Wilder's
Directional Movement Index (DMI) system. In the previous columns, we programmed the various
mathematical components of the system and now, with the tedious part behind us, the fun begins!
Knowing the trading rules and testing the results—and programming forces you to know the rules—is
what gives you an advantage over shoot-from-the-hip traders. If you can't specify your trading rules
clearly enough to test them, then why delude yourself into thinking you trade on the basis of rules?
I chose Wilder's DMI system for development in Lotus because important rules could not be observed
easily on graphs. In addition, research suggested that several of Wilder's rules go beyond what many
users of the DMI system incorporate into their testing (and presumably, incorporate into their trading). I
wanted to show the system fairly. Let's define the rules.