Latent Dirichlet Allocation (LDA) is an algorithm used to uncover the hidden topics in a text corpus. It is a generative probabilistic model of a collection of documents. It has been used to perform text analysis in natural language processing (NLP), in machine learning, and in quantitative marketing research.
At a basic level, LDA can be thought of as a process of multiple document clustering. It attempts to group related words into topics based upon their occurring patterns within a corpus of documents. Documents that contain more of the same words are grouped together. After the clustering is completed, the topics are labeled based on the underlying word patterns in the clustered documents.
Once the topics are labeled, LDA can be further used to uncover associations between topics and documents. For example, LDA can be used to infer whether or not a document contains a particular topic. In addition, it is used for applications such as document categorization, to help document mining, and natural language understanding.
LDA is closely related to probabilistic latent semantic analysis (PLSA) and can be thought of as a generalization from PLSA. Typically, it is applied to retrieving information from a large collection of documents. It has been used in a variety of industries, including healthcare, entertainment, and finance.
LDA is implemented using the Bayesian inference algorithm. Bayes’ theorem, named after the statistician Thomas Bayes, handles the probability measurements needed in order to properly classify words into topics. It is also possible to combine LDA with other methods such as markov chain Monte Carlo (MCMC) sampling to increase the effectiveness of the model.
Latent Dirichlet Allocation has become an increasingly popular algorithm due to its performance in natural language processing, machine learning, and quantitative marketing research. It provides a valuable way to understand the underlying structure of text corpora, uncover associations between topics and documents, and perform document clustering.