43. While it was noted earlier that the CPC basis of the ANZSCC enables improved comparability between production, import and export statistics, there are a number of factors for which allowance needs to be made when making comparisons. These include:
- the compatibility of the commodity categories at the detailed levels, discussed above;
- the units of quantity applicable to each series;
- the basis of valuation of the commodities concerned;
- timing in the recording of import and export movements, and in interpreting build up or run down of stocks by producers or merchants;
- the scope and coverage of collections; for example, the production of manufactured goods by business units whose primary industrial activity is predominantly non-manufacturing, is not covered by ABS Manufacturing Production statistics;
- differences in quality and material composition, or variations in the import component of goods, which may affect substitutability assumptions; and
- changes in the definition of individual commodities over time.