There is no single, formal definition of class status in this country. Statisticians and demographers all use slightly different methods to divvy up the great American whole into quintiles and median ranges. Complicating things, most people like to think of themselves as middle class. It feels good, after all, and more egalitarian than proclaiming yourself to be rich or poor. A $70,000 annual income is middle class for a family of four, according to the median response in a recent Pew Research Center survey, and yet people at a wide range of income levels, including those making less than $30,000 and more than $100,000 a year, said they, too, belonged to the middle.