While the study is Finnish I believe the same thing happens in the US.
Study: Working students get biggest payoff
A new report suggests that students who work while putting themselves through school have more success later than those who only focus on their studies.
University students who work in their own field while in school and graduate more quickly than average come out on top, according to a fresh report from the Ministry of Employment and the Economy. Only one in five of these go-getters are unemployed during the first five years of their career.
Study findings indicate that grades aren't the best predictors of work life success.
Students moving through the university system at an average or sluggish pace who don’t earn extra income while in school have a harder time breaking into the workforce than their employed counterparts.
The ministry found that students who are accepted into university directly from high school feel the least pressure to earn their diplomas quickly, thus taking the most time to complete their degrees.
Researchers interviewed some 2,500 students who graduated from the universities of Tampere, Turku, Oulu and Jyväskylä in 2005. The study was also based on archival information and employer surveys.