只在关键时用复杂模型,大部分时间用简单线性预测,效果不差还更透明。
AALF: Almost Always Linear Forecasting
- 动态选择模型:在线判断何时用深度学习,何时用简单线性模型。
- 多数情况选线性模型表现与顶尖方法相当,误差仅微增1.2%。
- 适合需要解释性的场景,如金融、医疗预测,提升决策可信度。
近期时间序列预测越来越多地采用深度学习模型以提升预测能力。然而,随着模型复杂度上升,其决策过程缺乏可解释性,这在高风险应用场景中存在问题。与此同时,像ARIMA这样的简单可解释模型仍能保持优异表现,有时甚至与深度学习方法不相上下。我们提出,简单模型在大多数情况下已足够,仅在少数关键预测中引入深度学习模型,即可提升整体可解释性并维持竞争力。为此,我们设计了一种新颖的在线模型选择框架,自动识别需使用复杂模型的时刻。在多个真实世界数据集上的大量实验表明,该方法在多数情况下性能接近当前最优在线选择方法,且可解释性显著提升。研究发现,几乎总是采用自回归线性模型进行预测,也能获得具有竞争力的结果,暗示时间序列预测对黑箱模型的需求可能被高估。
原文摘要 · Abstract (English)
Recent works for time-series forecasting more and more leverage the high predictive power of Deep Learning models. With this increase in model complexity, however, comes a lack in understanding of the underlying model decision process, which is problematic for high-stakes application scenarios. At the same time, simple, interpretable forecasting methods such as ARIMA still perform very well, sometimes on-par, with Deep Learning approaches. We argue that simple models are good enough most of the time, and that forecasting performance could be improved by choosing a Deep Learning method only for few, important predictions, increasing the overall interpretability of the forecasting process. In this context, we propose a novel online model selection framework which learns to identify these predictions. An extensive empirical study on various real-world datasets shows that our selection methodology performs comparable to state-of-the-art online model selections methods in most cases while being significantly more interpretable. We find that almost always choosing a simple autoregressive linear model for forecasting results in competitive performance, suggesting that the need for opaque black-box models in time-series forecasting might be smaller than recent works would suggest.
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