<p>Trevor Packer, College Board's executive director for the AP program, sent out a memo forwarded to various AP teacher email lists uncritically citing a statistical analysis reported in Jay Mathews' article in today's Washington Post.</p>
<p>You can see Mr. Packer's entire email in the public archives of the AP statistics teachers list at:
<a href="http://mathforum.org/epigone/ap-stat/drothunggler%5B/url%5D">http://mathforum.org/epigone/ap-stat/drothunggler</a></p>
<p>In his email, he writes: </p>
<p><< Especially profound are the findings demonstrating the impact of AP on students who attempt an AP course, but then only score a 1 or 2 on the AP Exam. The journalist [Jay Mathews] reporting this new research from the National Center for Educational Accountability goes so far as to say: "Every AP teacher in the country should copy that chart, blow it up to three-by-four foot size and tape it to the wall of his or her classroom." I encourage you to take a look at this article, and to share it with those who need more information about the impact AP is having on students, even those who may not succeed on the AP Exam.>></p>
<p>and he points the AP teachers to Jay Mathews' article containing the following table:</p>
<p>AP's Impact on Texas Students
Percent of Texas high school students receiving bachelor's degrees from Texas colleges and universities within five years of graduation:</p>
<p>Anglo (47,647 students) 57% 43% 22%
Hispanic (19,868 students) 47% 26% 8%
African American (7,813 students) 42% 36% 11%
Low-Income (22,028 students) 40% 24% 7%
Total (78,079 students) 57% 37% 17%</p>
<p>The first column lists the figures for students who passed an AP exam with a score of 3 or better, the second column lists the figures for students who took an AP exam but did not pass (scored a 1 or 2), and the third column lists the figures for students who did not take the exam. Thus, for example, among Hispanic students, 47% of those who passed the AP exam got their bachelors within 5 years of high school graduation, compared to 26% of those who got 1's or 2's, and only 8% of those who did not take an AP exam.
(Source Jay Mathews' article at:
<a href="http://www.washingtonpost.com/wp-dyn/articles/A6900-2004Nov23.html%5B/url%5D">http://www.washingtonpost.com/wp-dyn/articles/A6900-2004Nov23.html</a>)</p>
<p>Thus, what Jay Mathews and Trevor Packer are claiming is that these figures clearly demonstrate that the impact of taking AP is to raise greatly the probability that a given student will complete college within 5 years of high school graduation. </p>
<p>Not surprisingly, the AP statistics teachers are rather skeptical of this simplistic analysis. Some of their email responses to Mr. Packer's email point out that this is a classic illustration of how "correlation does not establish causality." Clearly students who CHOOSE to take AP exams differ in many important respect from those who choose not to take the exams. On average, those students who choose to take the exams will tend to be more motivated students and to have stronger academic backgrounds to begin with. </p>
<p>One imagines that if Mr. Packer and Mr. Mathews submitted such a superficial analysis on an AP Stats free response essay that these AP stats teachers would not give them a very high grade!</p>
<p>Now Jay Mathews' freely admits that he is befuddled by statistics, graphs, and charts. He states right up front in his article: " I do not use many charts and graphs in this column. They can be confusing, and I often don't understand them anyway." Like many journalists, it's clear he is more comfortable with words than with numbers. I wouldn't necessarily expect him to ace the AP statistics exam himself.</p>
<p>But the College Board is supposedly run by "psychometricians," who should, in theory, be careful in their use of statistics to support their conclusions. At a minimum, one would expect the head of the College Board's AP program to be capable of statistical analysis that would pass the AP statistics exam! </p>
<p>So I was pretty struck by Mr. Packer's failure to note that there are important statistical caveats that should be taken into account in drawing any conclusions about "the impact of AP on students who attempt an AP course."</p>