Definition: Symmetric index
Purchasing power parities
An index that treats the two countries being compared symmetrically by giving equal importance to the price and expenditure data of both countries. The price and expenditure data for both countries enter into the index number formula in a balanced or symmetric way.
A very similar definition is applied in the Consumer Price Index Manual (2004):
An index that treats both periods symmetrically by attaching equal importance to the price and expenditure data in both periods. The price and expenditure data for both periods enter into the index formula in a symmetric way.
Eurostat, Organization for Economic Cooperation and Development (OECD), "Eurostat-OECD Methodological Manual on Purchasing Power Parities", Publications Office of the European Union, Luxembourg, 2012