Jacqueline P. Leighton is Professor of Educational Psychology and Director of the Centre for Research in Applied Measurement and Evaluation (CRAME). She is also registered as a psychologist by the College of Alberta Psychologists. Her specialization is educational assessment and cognitive psychology, with an emphasis on test development and validity analysis. Dr Leighton's current research is on identifying and evaluating methods for generating cognitive models for educational assessment practice. Her research has been funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canadian Education Statistics Council (CESC) and is currently funded by the Social Sciences and Humanities Research Council of Canada (SSHRC).Mark J. Gierl is Professor of Educational Psychology at the University of Alberta. His specialization is educational and psychological testing, with an emphasis on the application of cognitive principles to assessment practices. Dr Gierl's current research is focused on differential item and bundle functioning, cognitively diagnostic assessment and assessment engineering. His research is funded by both the College Board and the Social Sciences and Humanities Research Council of Canada (SSHRC). He holds the Canada Research Chair in Educational Measurement.