I believe that PLSA is generally preferred over LSA, and LDA is preferred over PLSA. PLSA is equivalent to LDA when you assume the prior is a uniform Dirichlet

I believe that PLSA is generally preferred over LSA, and LDA is preferred over PLSA. PLSA is equivalent to LDA when you assume the prior is a uniform Dirichlet distribution. I guess LSA is probably the easiest to implement since it just involves a singular value decomposition, but I don't know how often it's actually used in practice anymore. http://en.wikipedia.org/wiki/PLSA http://en.wikipedia.org/wiki/PLSA http://en.wikipedia.org/wiki/Latent_Dirichlet_allocation http://en.wikipedia.org/wiki/Latent_Dirichlet_allocation