Trading this basic strategy without filtering any of the signals can result in whipsaws. A whipsaw is when there is a crossover in one direction, followed shortly after by a crossover in the other direction. Whipsaws can result in a number of losing trades in a short period of time.
To help avoid this, only take +VI crossovers (above VI) when the overall trend is up.
When the overall trend is down, only take -VI crossovers (above +VI).
In either case, use a crossover in the opposite direction as an exit signal. A manual stop loss should also be placed to control risk. For a long trade, place a stop just below a recent swing low, and for a short trade place a stop just above a recent swing high.
One way to analyse is the momentum change, if the current DI moment is greater than the high or lesser than the low of the previous cycles its considered to be a bullish / bearish signs.. Another way to look upon it is to see the retracements above/below 1 for signalled movements.
Its Professionally used as a Confirmation tool, Not a Decision tool!
Should be used when you see a Breakout, to confirm whether it is a false breakout or not! :)