In the United States, the concept of a working class remains vaguely defined and is especially contentious. Economists and pollsters in the United States generally define “working class” adults as those lacking a college degree, rather than by occupation or income. Many members of the working class, as defined by academic models, are often identified in the vernacular as being middle-class, there is considerable ambiguity over the term's meaning. Sociologists such as Dennis Gilbert and Joseph Kahl see the working class as the most populous in the United States, while other sociologists such as William Thompson, Joseph Hickey and James Henslin deem the lower middle class slightly more populous. In the class models devised by these sociologists, the working class comprises between 30% and 35% of the population, roughly the same percentages as the lower middle class. According to the class model by Dennis Gilbert, the working class comprises those between the 25th and 55th percentile of society. Those in the working class are commonly employed in clerical, retail sales, and low-skill manual labor occupations. Low-level white-collar workers are included in this class.
For purposes of political science, and less scientific or journalistic political analysis, defining the working class as less well educated workers is useful. One can then meaningfully analyze the political opinions and political behavior of, say, the white working class in the United States. In the case of the United States, for example, the white working class is often defined as "white" (i.e. non-Hispanic) workers who have not completed college.
Since the 1970s, economic and occupational insecurity have become a major problem for American workers, their families, and their communities. While out-sourcing, the busting and decline of unionization and welfare supports, and the rise of immigration, the prison-industrial complex and unemployment have brought increased competition and considerable economic insecurity to working-class employees in the "traditional" blue collar fields, there is an ever-increasing demand for service personnel, including clerical and retail occupations. Sociologist Gosta Esping-Anderson describes these supervised service occupations as "junk jobs", as they fail to pay living wages in the face of asset and price inflation, they fail to pay benefits, they are often insecure, unstable, or temporary, and they provide little work control and little opportunity for skill development or advancement. In contrast to other expensive countries with higher proportions of quality jobs, the U.S. has developed an economy where two-thirds of jobs do not require or reward higher education; the other one-third of jobs consist largely in managing the junk job workers. Recalling this American labor market reality as well as the high cost of higher education in the US, lower educational attainment can be a rational calculation. The alternative is probably not a better job. It is the junk job, with educational debt added on top. In fact, even if more Americans were to become highly educated, there would be more competition for the relatively few high quality jobs, and those wages would decline. This suggests that the middle and working classes in the US may not be distinct classes, but rather opposing subgroups of the same class.