Rate of Change is used to monitor momentum
by making direct comparisons between current and past prices on a continual basis. The
results can be used to determine the strength of price trends. Note: This study is the
same as the Momentum except that Momentum uses subtraction in its calculations while Rate
of Change uses division. The resulting lines of these two studies operated over the same
data will look exactly the same  only the scale values will differ. The Price
RateofChange ("ROC") indicator displays the difference between the current
price and the price xtime periods ago. The difference can be displayed in either points
or as a percentage. The Momentum indicator displays the same information,
but expresses it as a ratio.
When the RateofChange displays the price change in
points, it subtracts the price xtime periods ago from today’s price:
Today’s Close – Close x periods
ago
When the RateofChange displays the price change as a
percentage, it divides the price change by price xtime period’s ago:
