Historical Inertia: An Ignored but Powerful Baseline for Long Sequence Time-series Forecasting

Long sequence time-series forecasting (LSTF) has become increasingly popular for its wide range of applications. Though superior models have been proposed to enhance the prediction effectiveness and efficiency, it is reckless to ignore or underestimate one of the most natural and basic temporal properties of time-series, the historical inertia (HI), which refers to the most recent data-points in the input time series. In this paper, we experimentally evaluate the power of historical inertia on four public real-word datasets. The results demonstrate that up to 82% relative improvement over state-of-the-art works can be achieved even by adopting HI directly as output.