Because of the piecewise linear nature of the frontier in data envelopment analysis (DEA), estimated marginal rates of substitution are only valid for infinitesimal, or small finite, changes in one or more variables. Analysing the impacts of very small changes is not adequate for many...

The Malmquist index is a measure of productivity changes, of which an important component is the frontier shift or technological change. Often technological change can be viewed as a global phenomenon, and therefore individual or local measures of technological changes are aggregated into an...

For some investors their own personal investment counsellors address their investment strategy; for others automated means are used. To protect investors, the Canadian Government has enacted the "Know Your Client" Act requiring that all investment dealers and vendors of securities must know...

In two recent papers, Lozano and Villa [Centralized resource allocation using data envelopment analysis. Journal of Productivity Analysis 2004;22:143-61. [1]] and Lozano et al. [Centralized target setting for regional recycling operations using DEA. OMEGA 2004;32:101-10. [2]] introduce the concept of...