This page describes Flexible Parsing, a proposed extension for dictionary based compression schemes. Yossi Matias, Nasir Rajpoot, and Cenk Sahinalp have a summary of their work on this page, along with links to three PS format papers that go into detail on the results. The authors summarize this improved technique as “looking one step ahead for the longest phrase in the dictionary instead of trying to find the longest possible phrase at hand.”

http://www.dcs.warwick.ac.uk/~nasir/work/fp/