Underemployment reflects underutilization of the productive capacity of the labour force. Time-related underemployment, which is the only internationally accepted statistical definition of underemployment, examines the extent to which a person is insufficiently engaged in employment based on hours of work. Specifically, it refers to persons working part-time but are willing and able to engage in additional work.

Conceptually, there is also underemployment where the employment does not make full use of, or pay according to skills that workers could offer. This is more difficult to measure due to the subjectivity involved.

In Singapore, data on Time-related Underemployment are obtained from the mid-year Comprehensive Labour Force Survey and are published annually in the report on Labour Force in Singapore.

See also Employment and Unemployment.