The main step in calculating the ROC, is picking the "n" value. Short-term traders may choose a small n value, such as nine. Longer-term investors may choose a value such as 200. The n value is how many periods ago the current price is being compared to. Smaller values will see the ROC react more quickly to price changes, but that can also mean more false signals A larger value means the ROC will react slower, but the signals could be more meaningful when they occur.