Bill Shipley obtained his PhD in plant ecology from the University of Ottawa in 1987 and now teaches plant ecology and statistics at the Universite de Sherbrooke (Qc) Canada. He is the author of over 70 peer-reviewed papers in ecology and statistics, and Cause and Correlation in Biology: A User's Guide to Path Analysis, Structural Equations, and Causal Inference (Cambridge University Press, 2000).