Republicans are now arguing that Obamacare will lead to a 30-hour work week for most Americans because companies will try to keep hours worked for most of their employees below the 30-hour threshold that Obamacare defines as full-time work. So, is it happening? Nope.
Here is a chart showing the average hours per week Americans worked going back to 2006. Note that there was a big drop in average hours per week that people worked from mid-2008 to mid-2009 as a lot of people lost their full time jobs and had to take part-time work when they could get work at all. Starting in mid-to-late 2009 as the stimulus kicked in the average hours per week began to grow. It isn't quite back to where it was prior to the recession but it is close. If Obamacare were having an impact on work hour decisions by employers, we would expect to see average per week at 2009 levels are even declining. That just has not happened. In fact, the reverse has been true. If you can't see the chart, click on this link: http://advisorperspectives.com/dshort/updates/Employment-Wages-and-Hours.php
There is further evidence that Obamacare is having NO IMPACT on work hours. Jared Bernstein, a senior fellow at the Center for Budget and Policy Priorities in Washington compared projected involuntary part time work that we would expect given the current level of unemployment to the level we are actually seeing. Note: There is a relationship between involuntary part-time work and unemployment since more people are forced to take part time work when unemployment levels are high. Bernstein found that actual levels of involuntary part-time work are at just about where we would expect them to be given the level of unemployment and have tracked along with expectations throughout the recession and recovery. If Obamacare was leading to higher levels of part-time work then we would expect to see a deviation from what we migh expect—call it the Obamacare afffect. It just hasn’t happened. See Bernstein’s analysis here: http://economix.blogs.nytimes.com/2013/08/22/the-affordable-care-act-and-part-time-work/?_r=0