What is the unemployment rate?
The unemployment rate is the measure of the prevalence of unemployment (defined as people who are both jobless and looking for a job) within the total labor force.
The employment rate is considered a lagging indicator of market trends. While some degree of unemployment is expected, economists and policy makers get concerned when the unemployment rises above what the estimated normal unemployment would be in comparison to its GDP.
In the US, the unemployment rate is calculated by the Bureau of Labor Statistics and expressed as a percentage.
A related measure is the National Employment Report, which tracks private sector employment on a monthly basis.