“…Probabilistic topic modeling (and especially Latent Dirichlet Allocation) for information retrieval has been widely used recently in several ways (Andrzejewski, Buttler, 2011;Lu et al, 2011;Park, Ramamohanarao, 2009;Wei, Croft, 2006;Yi, Allan, 2009) and all studies reported improvements in document retrieval effectiveness. The main idea is to build a static topic model (using either LSA, pLSA, or LDA) of the collection, which will never be further updated, and to smooth the document language model by incorporating probabilities of words that belong to some topics matching the query (Lu et al, 2011;Park, Ramamohanarao, 2009;Wei, Croft, 2006;Yi, Allan, 2009).…”