Answer:
Productivity and specialization are both quite related to an entrance to the job market in a free market system.
Productivity is one of the most important viariables when entering the labor market. This is because wages depend mostly on the productivity of workers. The more productive you are, the higher your wage is likely to be.
Specialization is another important aspect. People who are highly specialized tend to be very educated and very productive, this means that a high degree of specialization is also predictive of a high wage.