increase in employment growth is now higher. This threshold has shifted outwards since the 1980s recession -- which is the topic of another research effort (more later). It has also been shifting out in the EU and Britain and I will comment more on that when I know more. But what about the US labour force data? First, it is true that the labour force participation rate has fallen significantly in the course of the recession and weak recovery. The following graph shows the labour force participation rate (using BLS data) from January 2002 to September 2012. The peak participation rate in the latest period was achieved in January 2007 (66.4 per cent), just before the storm hit. Later, I will show you what that means for the current unemployment rate. The labour force is a subset of the working-age population (those above 15 years old) and is the sum of total employment and total unemployment. The proportion of the working-age population that constitutes the labour force is called the labour force participation rate. So changes in the labour force can impact on the official unemployment rate and so movements in the latter need to be interpreted carefully. A rising unemployment rate may not indicate a recessing economy. The labour force can expand as a result of general population growth and/or increases in the labour force participation rates. What about the change between August 2012 and September 2012. The following table summarises the changes in the main labour force aggregates.