A comparison of text preprocessing techniques for hate and offensive speech detection in Twitter

Preprocessing is a crucial step for each task related to text classification. Preprocessing can have a significant impact on classification performance, but at present there are few large-scale studies evaluating the effectiveness of preprocessing techniques and their combinations. In this work, we explore the impact of 26 widely used text preprocessing techniques on the performance of hate and offensive speech detection algorithms. We evaluate six common machine learning models, such as logistic regression, random forest, linear support vector classifier, convolutional neural network, bidirectional encoder representations from transformers (BERT), and RoBERTa, on four common Twitter benchmarks. Our results show that some preprocessing techniques are useful for improving the accuracy of models while others may even cause a loss of efficiency. In addition, the effectiveness of preprocessing techniques varies depending on the chosen dataset and the classification method. We also explore two ways to combine the techniques that have proved effective during a separate evaluation. Our results show that combining techniques can produce different results. In our experiments, combining techniques works better for traditional machine learning methods than for other methods.