An information retrieval system uses an inverted indexing system composed of hybrid positional posting lists. A hybrid positional posting list includes a number of postings, where each posting contains a single numeric value to represent both the document containing a term and the location of the term in the document. When the number of postings for a document exceeds a threshold, a single-valued posting represents all the locations of a term in a document and the locations within the document. When the number of postings for a document is less than a threshold, each location of a term and the associated document is represented by a single-valued posting. In this manner, the storage requirements for the inverted indexing system are reduced and the processing speed increased.