Interpretability With Accurate Small Models

Models often need to be constrained to a certain size for them to be considered interpretable. For example, a decision tree of depth 5 is much easier to understand than one of depth 50. Limiting model size, however, often reduces accuracy. We suggest a practical technique that minimizes this trade-o...

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Main Authors: Abhishek Ghose, Balaraman Ravindran
Format: Article
Language:English
Published: Frontiers Media S.A. 2020-02-01
Series:Frontiers in Artificial Intelligence
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/frai.2020.00003/full
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author Abhishek Ghose
Balaraman Ravindran
author_facet Abhishek Ghose
Balaraman Ravindran
author_sort Abhishek Ghose
collection DOAJ
description Models often need to be constrained to a certain size for them to be considered interpretable. For example, a decision tree of depth 5 is much easier to understand than one of depth 50. Limiting model size, however, often reduces accuracy. We suggest a practical technique that minimizes this trade-off between interpretability and classification accuracy. This enables an arbitrary learning algorithm to produce highly accurate small-sized models. Our technique identifies the training data distribution to learn from that leads to the highest accuracy for a model of a given size. We represent the training distribution as a combination of sampling schemes. Each scheme is defined by a parameterized probability mass function applied to the segmentation produced by a decision tree. An Infinite Mixture Model with Beta components is used to represent a combination of such schemes. The mixture model parameters are learned using Bayesian Optimization. Under simplistic assumptions, we would need to optimize for O(d) variables for a distribution over a d-dimensional input space, which is cumbersome for most real-world data. However, we show that our technique significantly reduces this number to a fixed set of eight variables at the cost of relatively cheap preprocessing. The proposed technique is flexible: it is model-agnostic, i.e., it may be applied to the learning algorithm for any model family, and it admits a general notion of model size. We demonstrate its effectiveness using multiple real-world datasets to construct decision trees, linear probability models and gradient boosted models with different sizes. We observe significant improvements in the F1-score in most instances, exceeding an improvement of 100% in some cases.
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spelling doaj.art-b07998e388be4cde9a0e1982f2a0d9432022-12-22T01:35:10ZengFrontiers Media S.A.Frontiers in Artificial Intelligence2624-82122020-02-01310.3389/frai.2020.00003507097Interpretability With Accurate Small ModelsAbhishek Ghose0Balaraman Ravindran1Department of Computer Science and Engineering, IIT Madras, Chennai, IndiaDepartment of Computer Science and Engineering, Robert Bosch Centre for Data Science and AI, IIT Madras, Chennai, IndiaModels often need to be constrained to a certain size for them to be considered interpretable. For example, a decision tree of depth 5 is much easier to understand than one of depth 50. Limiting model size, however, often reduces accuracy. We suggest a practical technique that minimizes this trade-off between interpretability and classification accuracy. This enables an arbitrary learning algorithm to produce highly accurate small-sized models. Our technique identifies the training data distribution to learn from that leads to the highest accuracy for a model of a given size. We represent the training distribution as a combination of sampling schemes. Each scheme is defined by a parameterized probability mass function applied to the segmentation produced by a decision tree. An Infinite Mixture Model with Beta components is used to represent a combination of such schemes. The mixture model parameters are learned using Bayesian Optimization. Under simplistic assumptions, we would need to optimize for O(d) variables for a distribution over a d-dimensional input space, which is cumbersome for most real-world data. However, we show that our technique significantly reduces this number to a fixed set of eight variables at the cost of relatively cheap preprocessing. The proposed technique is flexible: it is model-agnostic, i.e., it may be applied to the learning algorithm for any model family, and it admits a general notion of model size. We demonstrate its effectiveness using multiple real-world datasets to construct decision trees, linear probability models and gradient boosted models with different sizes. We observe significant improvements in the F1-score in most instances, exceeding an improvement of 100% in some cases.https://www.frontiersin.org/article/10.3389/frai.2020.00003/fullMLinterpretable machine learningBayesian optimizationinfinite mixture modelsdensity estimation
spellingShingle Abhishek Ghose
Balaraman Ravindran
Interpretability With Accurate Small Models
Frontiers in Artificial Intelligence
ML
interpretable machine learning
Bayesian optimization
infinite mixture models
density estimation
title Interpretability With Accurate Small Models
title_full Interpretability With Accurate Small Models
title_fullStr Interpretability With Accurate Small Models
title_full_unstemmed Interpretability With Accurate Small Models
title_short Interpretability With Accurate Small Models
title_sort interpretability with accurate small models
topic ML
interpretable machine learning
Bayesian optimization
infinite mixture models
density estimation
url https://www.frontiersin.org/article/10.3389/frai.2020.00003/full
work_keys_str_mv AT abhishekghose interpretabilitywithaccuratesmallmodels
AT balaramanravindran interpretabilitywithaccuratesmallmodels