Autoregressive integrated moving average

Summary

An autoregressive integrated moving average model, or ARIMA($p$, $d$, $q$) model, is a time series model whose $d$-th differences form an ARMA($p$, $q$) process. It extends ARMA models to non-stationary series with trends or random-walk behaviour. The word "integrated" refers to undoing the differencing by summation. ARIMA models are among the most widely used models for forecasting economic and business series.