Multiblock and Multigroup PLS: Application to Study Cannabis Consumption in Thirteen European Countries

We address the problem of investigating the relationships between (K + 1) blocks of variables (i.e., K blocks of independent variables and one block of dependent variables), where the observations are a priori divided into several known groups. We propose a simple procedure called multiblock and multigroup PLS regression—which is a straightforward extension of multiblock PLS regression—that takes into account the group structure of the observations. This method of analysis is illustrated with a large, questionnaire based, survey exploring, in 2011, the cannabis consumption of teenagers of thirteen European countries (the European School Survey Project on Alcohol and other Drugs).