A mismatch in which a worker has a higher level of education than what is required for their job. This can result in underutilisation of skills, lower job satisfaction, and a reduced wage premium compared to jobs that fully utilise their qualifications. 

The additional earnings that workers receive due to higher education, experience, or specialised skills compared to those with lower qualifications. 

A situation where workers remain in low-skilled, low-wage jobs due to a lack of training, career progression opportunities. This can lead to a cycle of low productivity and stagnant wages.