Language Models and Smoothing Methods for Collections with Large Variation in Document Length

In this paper we present a new language model based on an odds formula, which explicitly incorporates document length as a parameter. Furthermore, a new smoothing method called exponential smoothing is introduced, which can be combined with most language models. We present experimental results for various language models and smoothing methods on a collection with large document length variation, and show that our new methods compare favorably with the best approaches known so far.