Not-so-naive Bayes

Despite being very simple, naive Bayes classifiers tend to work decently in some real-world applications, famously document classification or spam filtering. They don't need much training data and are very fast. As a result, they are often adopted as simple baselines for classification tasks. What many don't know is that we can make them much less naive by using a simple trick. Naive Bayes is a simple probabilistic algorithm that makes use of the Bayes' Theorem, hence the name.