The debate on whether there are wider economic benefits from transport infrastructure investments continues to cause debate and controversy. This debate occurs both between analysts seeking to find a robust method for identifying and measuring the size of such benefits and between policy makers seeking to justify or refute the need for a particular investment. It is timely to review progress on arriving at a consensus view of the contribution of infrastructure to the wider economy which is consistent with best practice in appraisal. This paper will review progress and try to bring out some common themes for discussion. The main aim of this paper is to bring together the various alternative methodological approaches to this problem which differs not just in the detail of the analysis, but more significantly in the scale at which the analysis is undertaken. It is argued that it is of particular importance to understand the way in which changes in the provision of transport affect microeconomic decisions, including those within firms and households, and to understand the operation of markets as well as to model the resultant flows and their macroeconomic consequences.