"After briefly analyzing the distribution of household money income in 2012, the report attempts to put the term 'middle class' into greater perspective. The first key point of the report is that, although there are a variety of ways to describe the income distribution, all show that income is concentrated among high-income households. […] The second major point is that there is no official government definition of who belongs to the middle class, and the term means different things to different people. The middle class may refer to a group with a common point of view or to those having similar incomes, for example. Third, absolute income appears to partly determine who belongs to the middle class. […] Last, relative income may also be a defining characteristic of the middle class. In other words, the middle class appears to identify itself relative to the income of a reference group (e.g., their neighbors or coworkers)."
CRS Report for Congress, RS20811