Autocorrelation Function
The autocorrelation function measures the linear relationship between a time series and a lagged version of itself at different time intervals. It helps traders and analysts understand the persistence of trends or the presence of cyclical patterns within market data.
If a series has high autocorrelation, it suggests that past price movements have predictive power for future price movements. In the context of market microstructure, the autocorrelation of order flow can reveal the presence of institutional activity or algorithmic trading patterns.
A decay in autocorrelation suggests that the market is efficient and that information is being incorporated into prices rapidly. This tool is fundamental for building models that predict volatility and identifying optimal entry points for trading strategies.