Tracking the middle class can be difficult, because the group is hard to define. Typically, researchers look at households with incomes or net worth in the middle of the entire population. This approach, though, might provide a falsely rosy picture. It doesn’t, for example, capture the fates of families that start out in the middle and — due to a job loss or other setback — end up in the bottom.
Two economists at the Federal Reserve Bank of St. Louis — William Emmons and Bryan Noeth — sought to address this shortcoming by focusing on households’ demographic characteristics, rather than income or wealth. Specifically, they looked at families whose breadwinner was at least 40 years old and had achieved a level of education that would typically allow a middle-class standard of living. Whites and Asians needed exactly a high-school diploma to qualify. For blacks and Hispanics, it took a two-year or four-year college degree — a stark recognition of persistent racial inequality.