arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.12483cs.LGq-fin.CPstat.ML
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选择特征的最佳方法是什么?

The best way to select features?

QTS Capital Management, LLC(QTS资本管理有限责任公司)

Xin Man, Ernest Chan

摘要:

机器学习中的特征选择受制于特征选择算法的内在随机性(例如,MDA期间的随机排列)。所选特征相对于这种随机性的稳定性对于机器学习算法的人类可解释性是必不可少的。我们提出了一个基于秩的稳定性度量称为不稳定性指数比较稳定性的三个特征选择算法MDA,石灰,SHAP适用于随机森林。通常,通过对选择算法的许多随机迭代求平均来选择特征。虽然我们发现所选特征的可变性确实随着迭代次数的增加而减少,但它不会变为零,并且三种算法所选的特征不一定收敛到同一集合。我们发现LIME和SHAP比MDA更稳定,LIME至少和SHAP一样稳定。因此,总体LIME最适合人类的可解释性。然而,从所有三种算法中选择的特征集显着提高了样本外的各种预测指标,并且它们的预测性能没有显着差异。实验进行了合成数据集,两个公共基准数据集,并从积极的投资策略的专有数据。

英文摘要:

Feature selection in machine learning is subject to the intrinsic randomness of the feature selection algorithms (for example, random permutations during MDA). Stability of selected features with respect to such randomness is essential to the human interpretability of a machine learning algorithm. We proposes a rank based stability metric called instability index to compare the stabilities of three feature selection algorithms MDA, LIME, and SHAP as applied to random forests. Typically, features are selected by averaging many random iterations of a selection algorithm. Though we find that the variability of the selected features does decrease as the number of iterations increases, it does not go to zero, and the features selected by the three algorithms do not necessarily converge to the same set. We find LIME and SHAP to be more stable than MDA, and LIME is at least as stable as SHAP for the top ranked features. Hence overall LIME is best suited for human interpretability. However, the selected set of features from all three algorithms significantly improves various predictive metrics out of sample, and their predictive performances do not differ significantly. Experiments were conducted on synthetic datasets, two public benchmark datasets, and on proprietary data from an active investment strategy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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