Value added estimates for different enterprise size classes are based on OECD Structural and Demographic Business Statistics (database) and will typically not align with estimates in national accounts. The latter include a number of adjustments to reflect businesses and activities that may not be covered in structural business statistics, such as those made to reflect the non-observed economy. In the absence of gross value added deflators by firm size class, deflators for gross value added in each industry are necessarily assumed to be equal across firm size classes and might affect the comparability across firms, industries and countries.
Since labour input is measured as total employment, comparability of labour productivity measures by size class may be affected by differences in the share of part-time employment. In addition, productivity differences in main aggregate sectors could mask different productivity patterns in more narrowly defined industries. This may in turn reflect differences in the value of goods and services produced, as well as different intensities in the use of knowledge-based capital.
Because the estimates presented here are not based on a fixed cohort of firms, estimates of productivity growth by firm size may be biased. SMEs exhibiting higher productivity growth at the start of the period are also more likely to become larger enterprises while low productivity large enterprises are more likely to contract and become SMEs.