# Advanced Placement exam cutoffs and superficial knowledge over deep knowledge

When I was in high school, I noticed is that it was possible to score the top mark on an [Advanced Placement (AP) Exam](http://en.wikipedia.org/wiki/Advanced_Placement_exams) by answering a relatively small portion of the questions correctly.

During my junior year, I self-studied calculus, and took the [AP Calculus AB](http://en.wikipedia.org/wiki/AP_Calculus#AP_Calculus_AB) exam. I was very surprised that I scored a 5 (the top mark), because at the time when I took the exam, I didn't know some very basic things that were on the syllabus.

The College Board gives the [raw score to AP score conversions](http://apcentral.collegeboard.com/apc/public/courses/212187.html) for the exams that have been most recently released. The percentages needed to get a 5 are as follows:

*   Art History: 71%
*   Biology: 63%
*   Calculus AB: 63%
*   Calculus BC: 63%
*   Chemistry: 67%
*   Computer Science A: 77%
*   English Language and Composition: 75%
*   English Literature and Composition: 76%
*   Environmental Science: 71%
*   European History: 66%
*   French Language: 80%
*   German Language: 86%
*   Comparative Government & Politics: 70%
*   US Government and Politics: 77%
*   Human Geography: 61%
*   Latin: Vergil: 69%
*   Music Theory: 70%
*   Macroeconomics: 81%
*   Microeconomics: 83%
*   Physics B: 62%
*   Physics C: Mechanics: 55%
*   Physics C: Electricity and Magnetism: 59%
*   Psychology: 75%
*   Spanish Language: 78%
*   Spanish Literature: 76%
*   Statistics: 63%
*   US History: 61%
*   World History 64%

Conspicuously, these percentages are all well below the standard 90% needed for the top mark (A) in a high school or college course. Of course, the threshold of 90% that's typically used is arbitrary, and some courses have harder exams than others, but the fact that the above percentages are lower than 90% (and in some cases \*much\* lower) is a [weak argument](/lw/hmb/many_weak_arguments_vs_one_relatively_strong/) that the standards for getting a 5 on an AP exam are lenient (and in some cases \*very\* lenient).

  

On an object level, based on my experience taking the AP calculus exams as a high schooler, my experience teaching calculus for three years at University of Illinois, and my revisiting the exams, I think that students who score 90% on an AP calculus exam know the material very well, and that students who score 63% (the lowest percentage needed to get a 5) have only marginal knowledge of the material.

  

It's natural to ask what effect this has on incentives. Note that AP courses are taught to prepare students to get high marks on the AP exams, so that the grading scheme for AP exams propagates backward to the grading schemes for courses, which feed into college admissions. Taking many AP courses and performing just above the "5" level looks better than taking few AP courses and performing at the ~90% level.

  

So one might reasonably suppose that high schoolers who want to get into selective colleges focus on developing superficial knowledge of lots of academic subjects rather than deep knowledge of a smaller number of academic subjects. And indeed, this is precisely what I remember most students doing in high school.

  

*   To what degree does your own experience reflect this as well?  
    
*   What are some other contexts in which this sort of thing occurs?  
    
*   How much of a problem is this (if at all)?