1. Greater earning potential
Dropping out of high school puts individuals at a disadvantage for life. Teens completing high school have greater lifelong earning potential than do their counterparts who did not graduate high school. Those who finish high school can expect to earn an average annual income of $30,766. Those who did not complete high school can expect to earn around $22,939 or less. This amount is roughly only two-thirds the income of those with a high school diploma making them more likely to need the help of public assistance.

A person’s lifelong earning potential rises in proportion to the level of education completed (Table 1). In addition to expecting to make more money, they can also expect to be able to get into the workforce quicker and have a greater chance of succeeding. The unemployment rate declines as level of education completed increases (Table 2).*

2. Improved chance of getting and keeping a job
Dropouts usually have difficulty finding and retaining jobs, unlike those who complete school. Dropping out of high school to get a job may seem like an attractive alternative, but rarely do such jobs offer opportunities for advancement or benefits. Companies that tend to hire persons without a high school diploma also tend to pay lower wages for the same jobs than do companies requiring a diploma.*

3. Better basic skills for getting along on the job
Those with higher levels of education find it easier to get and keep a job for two main reasons. One reason is that they can demonstrate that they have the basic job skills of reading, writing, math, communication and problem-solving needed for most jobs. Without these core skills, their choice of jobs is very limited. There was a time when a strong body and a willing spirit were enough to guarantee employment. With increasing emphasis on technical skills and more and more of the work once performed by employees now being accomplished by machines, these qualities may simply not be enough.*

4. Good work ethic and attitude
The other reason individuals with more education find it easier to find employment and remain employed is that they often have a good work ethic and a good attitude. The simple task of completing an education shows self-discipline and ambition.*


Source:
http://www.aces.edu/crd/workforce/publications/
08-30-02-BenefitsOfStayingInSchool.pdf