Provided are techniques for computer-based electronic Information Retrieval (IR). An extended inverted index structure by generating one or more lexical affinities (LA), wherein each of the one or more lexical affinities comprises two or more search items found in proximity in one or more documents in a pool of documents, and generating a posting list for each of the one or more lexical affinities, wherein each posting list is associated with a specific lexical affinity and contains document identifying information for each of the one or more documents in the pool that contains the specific lexical affinity and a location within the document where the specific lexical affinity occurs.