WEIGHTED COUNTRY PRODUCT DUMMY VARIABLE REGRESSIONS AND INDEX NUMBER FORMULAE

The article considers a very simple type of hedonic regression model where the only characteristic of a commodity is the commodity itself. This regression model is known as the country product dummy method for calculating country price parities in the context of making international comparisons. The paper considers only the two country or two period case and introduces value or quantity weights into the regression. The resulting measures of overall price change between the two countries or time periods are compared to traditional bilateral index number formulae. It is shown how the Geary Khamis, Walsh and Törnqvist price indexes can be obtained as special cases of this framework.