An extra year of college? There’s a cost to that.

Liberty Street Economics, the blog of the Federal Reserve Bank of New York, posted an interesting series last week on the value of a college degree. We’ve posted on this topic before, thanks to the Federal Reserve Bank of Cleveland, but in an era of ballooning college tuition costs and rising student loan debt, it’s a really important issue to continue to shine a light on.

Spoiler alert: the series concluded that having a college degree is still better than not having one (although the challenges facing recent college grads in securing good employment mean that a college degree will not be quite as lucrative as it used to be).

One of the series’ most interesting findings was that taking longer than four years to graduate from college can actually cost a graduate considerably more, not just in an extra year or two of tuition but in the opportunity costs from remaining a full-time student for an additional year or two.

According to the series’ authors, based on lifetime earnings profiles, “an extra year of staying in school costs more than $85,000, and for those who take two extra years to finish, it costs about $174,000.”

There are many reasons why students might take more than four years to complete a bachelors’ degree – but one big reason is being unprepared for the academic rigor of college. As we reported in the blog late last month, just 26 percent of the 1.8 million students who took the ACT last year met the college readiness benchmark in all four subjects tested (English, reading, math and science), according to a recent report by ACT. Students who aren’t ready for college-level work will often find themselves in remedial courses, which cost money but don’t get them any closer to their degree.

At Mass Insight, we believe that the best way to ensure students are ready for college-level work in college is to have more of them taking college-level classes while still in high school, through the Advanced Placement platform. And since students don’t just wake up in 11th grade ready for AP-level work, we also believe in working with teachers from sixth grade on to train them on how to increase the rigor in their pre-AP courses in order to grow the pipeline of future AP students.

Six years in, we’re seeing great results. Across the more than 70 Massachusetts high schools we’ve worked with, both participation in and performance on AP math, science and English courses have more than doubled. And students who have gone through our program are enrolling and persisting in college at rates higher than state and national averages.

Again, there are a lot of reasons why students might take more than four years to graduate from college. But given the financial implications laid out in the Liberty Street Economics blog, we should all be focused on making sure lack of academic readiness isn’t one of them.

To read the full Liberty Street Economics blog series, click here, here, here and here.