The derivative oscillator is a technical indicator that applies a MACD​ histogram to a double smoothed RSI to create a more advanced version of the RSI indicator. (It was developed by Constance Brown of Aerodynamic Investments and published in the book Technical Analysis for the Trading Professional.) It is displayed as a histogram. Positive readings are considered bullish, negative readings are considered bearish, and crossovers above and below the zero line signal indicate potential buying and selling opportunities.