The Regional Economics Applications Laboratory (REAL) is a cooperative venture between the University of Illinois and the Federal Reserve Bank of Chicago focusing on the development and use of analytical models for urban and regional economic development. The purpose of the Discussion Papers is to circulate intermediate and final results of this research among readers within and outside REAL. The opinions and conclusions expressed in the papers are those of the authors and do not necessarily represent those of the Federal Reserve Bank of Chicago, Federal Reserve Board of Governors or the University of Illinois. All requests and comments should be directed to Geoffrey J. D. Hewings, Director, Regional Economics Applications Laboratory, 607 South Matthews, Urbana, IL, 61801-3671, phone (217) 333-4740, FAX (217) 244-9339. Web page: www.uiuc.edu/unit/real AN INVESTIGATION OF INDUSTRY ASSOCIATIONS, ASSOCIATION LOOPS, AND ECONOMIC COMPLEXITY: APPLICATION TO CANADA AND THE UNITED STATES by Chokri Dridi and Geoffrey J.D. Hewings REAL 01-T-14 November, 2001 (Published in 2002: Economic Systems Research 14, 3, 275-296)