Correction and Update on APCS enrollment

July 21, 2009 at 12:07 pm 6 comments

About a month ago, I blogged on the impact of the Advanced Placement Computer Science (APCS) exam on undergraduate enrollment in computing. I cited some statistics about APCS that I have since discovered were wrong.  In particular, I claimed that there were 26 states whose total enrollment in APCS over the last 25 years has not been over 200.  That’s wrong.

Barb Ericson kindly gave me a spreadsheet with data from all 50 states over the last 10 years, so I can provide some more accurate observations.

  • In the 10 year window that Barb gave me, there 9 states whose total number of APCS seats (a student took the APCS Level A exam) is below 100.  Those states are (from fewest taking to most taking) are Montana (at 25 students from 1998 to 2008), North Dakota, South Dakota, Wyoming, Nebraska, Oregon, Kansas, Alaska, and Mississippi (at 198).
  • Those are also some of our least populous states, so those low numbers are not surprising.  There are fewer kids there (presumably) to take CS (though probably more than 200 high school kids total…)  What if we balance for state population?  Barb looked up the population in the state (total, not just of high school students, so it’s only a rough scaling factor) and came up a measure of tests taken in 2008 per million people, sortof a seats per capita.  There, Louisiana is lowest, with only 1.36 tests taken per million people. Montana, Wyoming, and Idaho are tied at 2.
  • There are 18 states with less than 20 seats (on the 2008 exam) per million, which I’m using as a rough benchmark of “There’s one APCS teacher teaching one class of CS students per million people.” Some of those were pretty surprising to me: Iowa at 7 (21 students took it, with roughly 3 million people), Oregon at 8.78, Arizona at 10.8, Utah at 12.6, and West Virginia at 13.3.  Just outside my metric (tied at 21) are New Mexico, Michigan, and Minnesota.
  • Who leads in producing APCS students? Maryland is the highest seats-per-million at 160.  The rest of top 10 are Texas, Virginia, Washington DC (51 students for 600K population), New Jersey, Connecticut, Georgia, Hawaii, California, and New York.

Overall, 15,014 students took the APCS Level A exam in 2008.  Just shy of half of those students (48%) came from three states: California, Texas, and New York.

In contrast, in 2008, 222,835 students took the AP exam for Calculus (Level AB).  57,758 took the AP exam for Physics Level B.  If we were to assume that high schools were perfect economic beings, and the number of those taking the test is a true indication of the importance of the field, then CS is 6% as important as Calculus, and 26% as important as Physics.

The College Board has found in its studies that 58% of high school students who take an APCS course end up taking a computer science course in college, and 19% of those pursue a computing degree – regardless of whether the students even take the exam.  In comparison, only 28% of high school students who do not take any APCS exam go on to take a computer science course, and only 3% of those students pursue a computing degree.  Simply taking the APCS course has an important impact on improving enrollments in computing.

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Feynman lectures from Microsoft: A medium for active essays and computing ed The Economics of Computing Education

6 Comments Add your own

  • 1. Andrew Miller  |  July 21, 2009 at 12:56 pm

    Great post! One minor quibble: I’d be hesitant to conclude, as you do, that “simply taking the APCS course has an important impact on improving enrollments in computing.” Rather, isn’t enrollment in the APCS course itself an indicator of future interest in computing? Unless the APCS student pool is randomly assigned, I’d guess there’s a heavy selection effect going on here.

  • 2. Mark Guzdial  |  July 21, 2009 at 1:10 pm

    Thanks, Andrew! Yes, there is a selection effect going on, but that’s part of “simply taking the ACPS course.” Getting more students into APCS should have the effect of increasing CS enrollment, given the observed probabilities described by the College Board. I’m not claiming that making students take the APCS will create more computing majors.

    • 3. Andrew Miller  |  July 21, 2009 at 1:15 pm

      Ah I see your point now. The idea is that because enrollment is smaller than the pool of those who might be interested, the positive effects are not getting to all those who might benefit. Thanks again!

  • 4. Leigh Ann  |  July 21, 2009 at 4:49 pm

    I keep a book. Every year that I taught I took a picture with my seniors and then they wrote in my book the way they would write in a yearbook. You would not believe the number of students who said that they took the course because they were “curious” and that the courses lead them to become computer science majors.

    Its hard to take a leap of faith and enroll at a college or university with a major that you have never tried or seen. Without high school computer science, we do not offer the opportunity to try computer science before they need to declare it their lifelong career. APCS lends legitimacy to the high school courses, and offers a curriculum that standardizes what is taught in those classes. It raises a school’s image by being able to increase the number of APs they offer and raise the number of students taking AP.

    We did not define nor can we change the political reality that AP subjects lend credibility and are a powerful chip for schools. We just need to recognize that students need a chance to try things before they select a major – which despite all of our comments that it does not define you – feels a lot like you are defining yourself for the rest of your life.

  • 5. Jeff Graham  |  July 28, 2009 at 2:33 pm

    How many states actually offer certification in computer science? I know Pennsylvania doesn’t. I think North Carolina doesn’t although it has (?) something called an endorsement you can add on to another certificate. Seems like a chicken and egg problem, we have no teachers so we have no students. My local school district likes to talk about “technology” but they don’t offer but one programming class. I don’t have any ideas how computer science can become a mainstream subject. I think ideally it would be introduced in elementary school. As it is now, the pinnacle of computer related stuff seems to be PowerPoint. Ugh.

    • 6. Mark Guzdial  |  July 28, 2009 at 3:07 pm

      Jeff, the CSTA ( has a report on what kind of teacher certifications (or endorsements, which is what Georgia has, too). It’s a highly-constrained problem. Yes, you need certifications, but even before that, you need computing courses to show up in the state (and sometimes, district-level) curriculum, and it helps if APCS counts towards high school graduation (only Georgia and Texas have that). So you need the curriculum to offer the classes, you have to have the classes actually offered by the high schools, and you have to have teachers for those courses — certification for those teachers would be nice, too!


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