Generating Human Understandable Explanations for Node Embeddings

TL;DR

This paper introduces XM, a framework that explains node embeddings with human-understandable features and modifies existing algorithms to produce more explainable embeddings without sacrificing performance.

Contribution

The paper demonstrates that node embedding dimensions can be explained by graph features and presents XM, a method to enhance explainability while maintaining embedding quality.

Findings

Node embedding dimensions can be explained by graph features.

XM improves explainability of embeddings.

XM preserves the performance of existing embedding algorithms.

Abstract

Node embedding algorithms produce low-dimensional latent representations of nodes in a graph. These embeddings are often used for downstream tasks, such as node classification and link prediction. In this paper, we investigate the following two questions: (Q1) Can we explain each embedding dimension with human-understandable graph features (e.g. degree, clustering coefficient and PageRank). (Q2) How can we modify existing node embedding algorithms to produce embeddings that can be easily explained by human-understandable graph features? We find that the answer to Q1 is yes and introduce a new framework called XM (short for eXplain eMbedding) to answer Q2. A key aspect of XM involves minimizing the nuclear norm of the generated explanations. We show that by minimizing the nuclear norm, we minimize the lower bound on the entropy of the generated explanations. We test XM on a variety of real-world graphs and show that XM not only preserves the performance of existing node embedding methods, but also enhances their explainability.