When recessions hit, we historically see a conversion of full-time workers into part-time workers. This is visible in the recession of 2008-2009.
The increase in part-time workers is also visible in the chart below, which shows how many hours people work per week. We see that the average weekly hours dropped in the 2008-2009 recession and it is starting to drop in 2014. This means that a new recession is in the making in 2014. The key is to predict recessions by looking at the increase in part-time employment.
When Obamacare rolls out in 2014, we will continue to see a shift to part-time employment as employers will fire full-time workers (>30 hours/week) and hire part-time workers (<30 hours/week) to avoid paying for Obamacare.