Or's of And's for Interpretable Classification, with Application to Context-Aware Recommender Systems
This work addresses the need for interpretable machine learning models in domain-specific applications like recommender systems, though it is incremental as it builds on existing pattern-based methods.
The paper tackles the problem of building interpretable classifiers using disjunctions of conjunctions (or's of and's) and presents Bayesian Or's of And's (BOA) models with scalable inference methods, applying them to context-aware recommender systems for predicting user behavior.
We present a machine learning algorithm for building classifiers that are comprised of a small number of disjunctions of conjunctions (or's of and's). An example of a classifier of this form is as follows: If X satisfies (x1 = 'blue' AND x3 = 'middle') OR (x1 = 'blue' AND x2 = '<15') OR (x1 = 'yellow'), then we predict that Y=1, ELSE predict Y=0. An attribute-value pair is called a literal and a conjunction of literals is called a pattern. Models of this form have the advantage of being interpretable to human experts, since they produce a set of conditions that concisely describe a specific class. We present two probabilistic models for forming a pattern set, one with a Beta-Binomial prior, and the other with Poisson priors. In both cases, there are prior parameters that the user can set to encourage the model to have a desired size and shape, to conform with a domain-specific definition of interpretability. We provide two scalable MAP inference approaches: a pattern level search, which involves association rule mining, and a literal level search. We show stronger priors reduce computation. We apply the Bayesian Or's of And's (BOA) model to predict user behavior with respect to in-vehicle context-aware personalized recommender systems.