10.06 Amongst the flows, which appear in economic accounts at current prices, there are some (mainly concerning products) where the distinction between changes in price and volume is similar to that made at micro-economic level. For many other flows in the system, the distinction is far less obvious.
In the former case, the flows cover a group of elementary transactions in goods and services, the value of each being equivalent to the product of a number of physical units and their respective unit price. In this case it is sufficient to know the breakdown of the flow in question into elementary transactions in order to determine its average variation in price and volume.
In the latter case, which concerns a number of transactions relating to distribution and financial intermediation as well as to balancing items such as value added, it is difficult or even impossible to separate directly current values into price and volume components and special solutions have to be adopted.
There is also a need to measure the real purchasing power of a number of aggregates, such as compensation of employees, disposable income of households or national income. This can be done, for example, by deflating them by means of an index of the prices of the goods and services which can be bought with them.
10.07 It must be emphasised that the objective and the procedure followed when measuring the real purchasing power are fundamentally different from those followed when deflating goods and services and balancing items. For these an integrated system of price and volume indices can be established, which is useful, amongst other things, for measuring economic growth. The valuation in real terms of flows of the last type uses price indices of flows other than those considered, which may differ according to the objectives of the analysis: it can only be a convention and cannot be done in a unique way within an integrated system of price and volume indices.