Every fall, nearly 70 percent of new high school graduates start college. For parents, the expectation is that a few years later their children will get another diploma at college commencement.

That’s what I frequently heard from parents of high-school seniors who I met in the past few months while on tour for my new book about how to navigate the undergraduate years to succeed in the workforce after college. These parents were mostly worried about their teenagers getting into college and how to pay for it, not what happens once they are on campus. The widespread assumption is that if your children finish high school and go to college, they’ll graduate.

Think again.

Two new reports out this month describing who completes college and the warning signs for students at risk of dropping out paint a picture of a much different future than the one most parents imagine for their kids.

The first study released this week looks at completion rates for students who entered college in fall 2010. Because graduation rates in the report vary widely depending on a variety of factors — where students go to college and when in life they go — let’s focus on the typical teenager who graduated from high school in 2010 and headed right off to college the following fall.

Among that group of students, 60 percent finished college in six years, according to the National Student Clearinghouse Research Center. What happened to the rest of them? Some 26 percent dropped out and 14 percent were still enrolled after six years.

A closer look at the numbers reveals some interesting trends for this year’s seniors and their parents as they consider where to go to college next year.

For one, women are much more likely than men to make it to graduation day (65 percent of women finished in six years compared to 56 percent of men). Second, where you go to college matters. Of those teenagers who enrolled in private colleges in 2010, 74 percent completed in six years compared to 62 percent of those who went to public universities. Third, go to school full-time if you can afford it. Full-time students were twice as likely to graduate compared with those who alternated between going full-time and part-time.

A second study released today comes through a trove of data collected from 4 million student records at 68 colleges and universities that are clients of Civitas Learning.

The company, based in Austin, is part of a growing array of education technology firms that help colleges and universities mine their student data to better predict where students might run into trouble with specific courses or majors. The theory behind these “predictive analytics” tools is the same one that drives the invisible algorithms that recommend music on Spotify and movies on Netflix based on your previous purchases.

The statistics from Civitas refute many long-held beliefs about who is likely to succeed in college and why students drop out. Students with the worst grades, for instance, are not always the first to leave. Nearly all of the institutions in the Civitas study, which included nearly two dozen selective colleges and 16 research universities, lost more students with grade-point averages above 2.0 than below it. Some 44 percent of the students who dropped out of school had GPAs between 3.0 and 4.0.

The study noted that most colleges focus their retention efforts on freshmen with low grades, but among the students who completed their first year, few with low GPAs ended up leaving. “In essence, much of our focus is directing remedies to the wrong patients,” the report said.

The Civitas study also serves as a reality check for parents who think that as long as their kids go to selective colleges with tough admissions standards and do well that they’ll graduate and for high-school counselors who believe that standardized test scores are the best predictors of success in college.

The data show that grades are not the only signal that students might be struggling in college. At selective schools in the study, for instance, among the students who left, the biggest group were those who had GPAs above 3.0 (they accounted for 40 percent of those who dropped out). The “tipping point” for the GPA at a selective college — in other words, the mark where a student is more likely to stay or leave — is a 2.5 for first-year students and a 2.7 for other undergraduates, well above the 2.0 that has traditionally been set by colleges.

In looking at a smaller subset of high-school records affiliated with the colleges Civitas works with, the company found that SAT and ACT scores were much less predictive of performance in college than a student’s high-school experience.

Taken together, these two studies show that how students go to college matters more than the test scores they put on an admissions application or the grades they get once in college.

For many students and their parents and counselors, getting accepted to college is about jumping through all the right hoops. Unfortunately, little thought is given to what is next: what they’ll do once on campus. Too many students sit back and wait for professors to deliver lessons in the classroom without actively participating or fail to chase after experiences like study abroad or undergraduate research or cultivate relationships with professors who can serve as mentors.

If students treat college like a spectator sport, it’s likely the game will end early for them.