An autocorrelation of +1 represents a perfect positive correlation, while an autocorrelation of negative 1 represents a perfect negative correlation. Technical analysts can use autocorrelation to measure how much influence past prices for a security have on its future price.
How do you evaluate autocorrelation?
Autocorrelation is diagnosed using a correlogram (ACF plot) and can be tested using the Durbin-Watson test. The auto part of autocorrelation is from the Greek word for self, and autocorrelation means data that is correlated with itself, as opposed to being correlated with some other data.
What information does autocorrelation give us?
The autocorrelation function (ACF) defines how data points in a time series are related, on average, to the preceding data points (Box, Jenkins, & Reinsel, 1994). In other words, it measures the self-similarity of the signal over different delay times.