A more sophisticated approach is offered by advanced statistical techniques like (multiple) regression analysis. Such a technique allows the influence of individual variables to be assessed, so that the variation in rents can be assigned to certain characteristics. Briefly, the explanatory power of a variable can be quantified (via the correlation coefficient). As a by-product, it enables the characteristics to be ranked according to their importance. This helps to determine where to stratify in greater detail. Combining the most important variables, using multiple regression techniques, shows their overall explanatory power. The use of advanced statistical techniques to select important variables is considered to be an efficient way of stratifying the housing stock. In addition, such techniques would seem to be a useful tool for estimating the average rent in cases where there are no corresponding observations in the rented sector (empty strata).
