  We propose an inlier-based outlier detection method capable of both
identifying the outliers and explaining why they are outliers, by identifying
the outlier-specific features. Specifically, we employ an inlier-based outlier
detection criterion, which uses the ratio of inlier and test probability
densities as a measure of plausibility of being an outlier. For estimating the
density ratio function, we propose a localized logistic regression algorithm.
Thanks to the locality of the model, variable selection can be
outlier-specific, and will help interpret why points are outliers in a
high-dimensional space. Through synthetic experiments, we show that the
proposed algorithm can successfully detect the important features for outliers.
Moreover, we show that the proposed algorithm tends to outperform existing
algorithms in benchmark datasets.
