type="main" <p>Non-linear pricing, the fact that prices do not necessarily change in proportion to size, is a ubiquitous phenomenon. However, it has been neither particularly well understood nor well measured. Non-linear pricing is of practical importance for statistical agencies who, in...</p>

A justification for the use of the EKS multilateral index can be given from the economic approach to index numbers. Copyright 2003 by the International Association for Research in Income and Wealth.