RSI and moving average convergence divergence (MACD) are both momentum measurements that can help traders understand a security’s recent trading activity. However, they accomplish this goal in different ways. In essence, the MACD works by smoothing out the security’s recent price movements and comparing that medium-term trend line to a short-term trend line showing its more recent price changes. Traders can then base their buy and sell decisions on whether the short-term trend line rises above or below the medium-term trend line.