Most students that drop out of college in the US do so because they cannot afford to pay for the rising cost of tuition, according to a report released Wednesday by Public Agenda, a non-profit research institute.

The study, which surveyed 600 people ages 22 to 30, found that less than half of students graduate on schedule after signing up for a two or four-year program.

The report, entitled “With Their Whole Lives Ahead of Them,” notes that only about 20 percent of US students who start a two-year college program finish within three years, and only about forty percent of those who start at a four-year university finish within six years.

To explain its results, the study notes that the price of a college diploma has more than quadrupled in the past 25 years, while the median family income has increased only 150 percent during that time.

Only 10 percent of students who drop out report that boredom or lack of interest in the classes were significant influencing factors. Most students who left their classes would have liked to stay, but could not balance their curriculum and their financial obligations.

According to the study, “Most students leave college because they are working to support themselves and going to school at the same time. At some point, the stress of work and study just becomes too difficult.”

Nearly half of students at four-year universities work 20 or more hours a week. For community colleges, the figure jumps to sixty percent, while more than a quarter work 25 hours or more. These numbers point to the large proportion of students trying to earn degrees without significant help from parents, social services, or the government.

The study observes that the “traditional college experience” is nonexistent for most students. Only a quarter of students live on campus and “attend the sort of residential college we often envision.” Twenty-three percent of college students have dependent children.

Seventy-one percent of students who dropped out reported needing “to go to work and make money” as one of the reasons for leaving, while 52 percent reported that they “just couldn’t afford the tuition and fees.”

One young woman who had dropped out but recently started taking classes again told the surveyors, “It’s very hard because I go to school three nights a week. I work from 8 to 5. I don’t get home until 9:30, 10 at night… I also think my dedication to my classes could be better if I didn’t work as much.”

Nearly a third of people who left the university early reported that they took on student loans, despite not having the career advantages conferred by a diploma. The study notes: “In many respects, they have the worst of both worlds—no diploma, but college loans to repay.”

Seventy percent of dropouts said they had no scholarships or student loan assistance. By contrast, only 40 percent of graduates reported getting no such aid. The odds of graduating are stacked most heavily against students who do not have parental support and, seeking to avoid a lifetime of indebtedness, are unwilling to take on student loans.

The average student who graduated in 2008 owed $23,000 in student loans, according to a separate report by the Project for Student Debt. This is under conditions where the unemployment rate for college graduates aged 20 to 24 reached 10.6 percent in the third quarter of the year, up from 7.6 percent a year before.

Conditions are even worse for young people looking to keep a job through high school and college. The unemployment rate for people aged 16 to 19 reached 26.7 percent in November of this year, up from only 20.2 percent a year earlier.

Tuition is not the only reason why students drop out; the rising cost of living is also important. Over one third of students who dropped out but wanted to return to college said that they would not be able to do so even if their tuition and books were fully paid for.

The conditions described in the report are the product of a concerted attack on public education. In the midst of the greatest budgetary crisis in postwar history, the Obama administration has withheld all discretionary assistance from states, aside from the completely inadequate stimulus bill passed earlier this year. States have been forced to cut student services and raise tuition in response, moving higher education further out of reach of many working class students.