During the 2008 presidential campaign, Barack Obama said he would "set a goal of increasing the number of high school students taking college level or AP courses by 50 percent in the coming years."

AP, or advanced placement, courses are taken in high school and can be used for college credit if the student earns a high enough score on the final exam. On this metric, Obama hit his target.

Data from the College Board, which runs the AP program, shows that the number of students taking AP courses rose from 1.58 million in the 2007-08 academic year to 2.61 million in the 2015-16 academic year. That's a 65 percent increase -- well above Obama's goal.

If you instead use the 2008-09 academic year as the baseline, the increase is still greater than 50 percent -- 54 percent, to be precise.

College Board spokeswoman Jaslee Carayol said that much of the AP participation growth has come from low-income AP test-takers. Using a federal fee-reduction program called the Advanced Placement Test Fee Program, the number of AP exams taken by low-income students has grown from 82,000 in 1999 to 850,000 in 2016.

We'll also note that in his promise, Obama also mentioned high school students taking college level courses, often referred to as dual enrollment. By that measurement, he didn't do quite as well, but he still notched a significant double-digit increase.

Experts told us it's hard, given the timing and availability of the relevant statistics, to check progress on this goal directly. But they added that the number can be approximated by looking at the percentage of college students who are under 18.

Data from the Department of Education's Integrated Postsecondary Education Data System showing that in fall 2007 -- the last sampling before Obama took office -- 683,673 students under 18 attended some college. By fall 2013, that number had risen to 885,104 -- a 29 percent increase. If the data were projected forward from 2013 based on past growth rates, the increase would be somewhere around 40 percent.

In isolation, this "dual enrollment" falls short of the 50 percent increase Obama called for. However, Obama did refer to students "taking college level or AP courses," which suggests that he was looking at the combination of both. And if you combine the two types of data, the increase has been over 50 percent.

Observers said Obama deserves at least partial credit for achieving this result.

"The Obama administration has done a considerable amount to encourage states and school districts to increase dual enrollment opportunities through written policy and grant guidelines in programs such as ESEA Waivers, Investing in Innovation Fund, Race to the Top, School Improvement Grants, College Access Challenge Grants, Promise Neighborhoods, and the Fund for Improvement in Postsecondary Education," said Adam I. Lowe, executive director of the National Alliance of Concurrent Enrollment Partnerships.

We rate this a Promise Kept.

When presidential candidates make campaign promises about improving the country's education system, they should keep this in mind: It will be difficult to prove you made a difference.

We saw that recently with a promise about improving the nation's high school graduation rate, which we concluded should remain In the Works indefinitely because imperfect and delayed measurements won't reflect Obama's impact for years to come.

Here's another example: Barack Obama told voters he would get more high school students taking college-level or advanced placement courses. He said his goal was to increase the number by 50 percent "in the coming years.”

Any time you promise to improve performance, you need a baseline. A new runner might record a mile time with no training, and then record another mile six months down the road.

When it comes to high school students taking college-level courses, no one recorded the baseline number at the start of Obama's term. Actually, to a large extent, no one knows the number even today.

"It's not something that's well tracked on a national basis,” said Christina Clark Tuttle, a senior researcher at Mathematica Policy Research, a nonpartisan policy think tank.

The U.S. Department of Education does conduct one longitudinal study that suggests the percentage of public high school graduates taking college-level courses is increasing: 34.9 percent in 2005 and 41.4 percent in 2009.

In general, secondary education researchers differentiate between two types of college-level courses: those designed to prepare students to take an Advanced Placement exam and so-called concurrent enrollment or dual-credit courses. Obama seemed to be referring to both types in his campaign pledge.

The College Board reports that the number and percentage of public high school graduates taking Advanced Placement exams increased steadily during President George W. Bush's two terms, and the trend continued under Obama. The percentage of public high school graduates taking Advanced Placement exams climbed from 16.8 percent in 2001 to 30.2 percent in 2011.

Now this doesn't quite match Obama's pledge. He referred to increasing the number of students taking Advanced Placement courses, which might correlate with taking the related exams. However, not everyone who takes a course takes the exam and the College Board doesn't track AP course enrollment.  

Here's the trickier question: How many students are taking other kinds of college-level courses and how did that change?

Tuttle, of Mathematica, said states count college-level courses differently and some states don't track college-level courses taken by high school students at all, making it difficult to draw definitive conclusions about nationwide trends.

It's plausible that Obama's signature K-12 education initiative, Race to the Top, has triggered progress on this front, and we just don't know it yet. The program uses the allure of grant funding to compel states to change their own education standards in the hopes of winning federal money. One of the many criteria by which the federal government grades states is the number of students who complete at least a year's worth of college credit.

"Dual enrollments seem to me to be increasing because there are a range of incentives and policies which are encouraging more schools, colleges, and students to participate. My sense is that it's on the rise fairly widely,” said Elisabeth Barnett, a post-secondary education researcher at Columbia University's Teacher College.

Barnett's observation aligned with other experts we interviewed. Even so, no data exists yet to prove more high school students took college-level courses under Obama -- especially not 50 percent more. Until we see evidence to the contrary, we'll leave this In the Works.

President Obama has packed a number of his campaign promises related to education into his "Race to the Top" program, which seeks to encourage innovative approaches to teaching and learning by having states compete for $4.35 billion worth of grants from the Department of Education. The program was funded through the Obama-backed economic stimulus package approved by Congress in February.

The grants are designed to encourage state programs that achieve "significant improvement in student outcomes, including making substantial gains in student achievement," according to a Department of Education notice inviting applications. Later, the notice defines student achievement, which includes increasing the "percentage of students enrolled in Advanced Placement courses who take Advanced Placement exams."

Advanced Placement courses are essentially college-level courses taught in high school. Students who pass advance placement exams are eligible for college credits at most U.S. colleges.

Competition for the "Race to the Top" grants will be conducted in two rounds -- the first starting this month and the second in June of next year -- with winners announced in April and September 2010.

Whether these grants will do enough to encourage high schools to increase the number of students taking college level or AP courses by 50 percent in the coming years remains to be seen. But it's a start. And so we move this one to In the Works.