Main Path Analysis

Main path analysis (MPA) traces the principal trajectory of knowledge development through a citation network. Introduced by Norman Hummon and Patrick Doreian in their 1989 study of the discovery of DNA, the method treats a field's literature as a directed acyclic graph in which documents point backward in time to the work they cite. Rather than mapping the whole network, MPA weights each citation link by how central it is to the flow of ideas — how many knowledge-carrying paths run through it — and then extracts the chain of most-traversed links from the field's earliest sources to its most recent sinks. The result is a compact 'main path': an ordered sequence of papers that represents the backbone along which a research front actually developed.