Random article: Rate of Change (ROC)
ROC indicator relates to anticipating figures, however, in terms of logic, if price factor is removed from calculation, the indicator stops operation and anticipation does not work as well. Still the point of anticipation is the following: when trend starts losing its force and slows down, the indicator's values begin pivoting, whereas price still can continue its movement along trend. In other words, as many other oscillators, ROC shows divergence and convergence. Of course, many things depend on parameters chosen by trader.