I've just started at <a href=" http://nobrow.net/paravol-price.pptx#switch ">paravol cost</a> What does &#8220;middle class&#8221; mean? President Obama is set to make a speech tomorrow where he&#8217;ll try to turn attention back to the economy and the middle class. But there&#8217;s a big problem&#8230; there&#8217;s no set definition of what the middle class is.