This paper argues that in the United States the full-employment rate of unemployment (FERU) is the geometric average of the unemployment and vacancy rates. Between 1930 and 2024, the FERU averages 4.1% and is very stable.
US unemployment rate The unemployment rate is the number of job seekers divided by the number of labor force participants. It measures the share of the labor force that is unemployed. The numbers of job seekers and labor force participants are both measured by the US Bureau of Labor Statistics (BLS) from the Current Population Survey (CPS), which is a large-scale household survey. ...