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arXiv · 2404.18190

Naive Bayes Classifiers and One-hot Encoding of Categorical Variables

Christopher K. I. Williams
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Abstract

This paper investigates the consequences of encoding a $K$-valued categorical variable incorrectly as $K$ bits via one-hot encoding, when using a Na\"{\i}ve Bayes classifier. This gives rise to a product-of-Bernoullis (PoB) assumption, rather than the correct categorical Na\"{\i}ve Bayes classifier. The differences between the two classifiers are analysed mathematically and experimentally. In our experiments using probability vectors drawn from a Dirichlet distribution, the two classifiers are found to agree on the maximum a posteriori class label for most cases, although the posterior probabilities are usually greater for the PoB case.

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Christopher K. I. Williams. 2024-04-28. Naive Bayes Classifiers and One-hot Encoding of Categorical Variables. https://arxiv.org/abs/2404.18190

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