The College Board debuted the AP Computer Science Principles course in 2016 and, by 2019, over 100,000 teens were sitting for the exam each year. In further evidence of the course’s success, female test-takers increased 136% in that timeframe. By 2021, there were 116,000 exam-takers, a 21% increase over two years prior. Meanwhile, the old standard—Computer Science A—has been around since 1984 and remains highly popular as well, with almost 75,000 high schoolers taking the course last year. With two Advanced Placement CS courses on the menu, students and parents naturally want to fully understand the differences between AP Computer Science Principles vs AP Computer Science A.

In the interest of leading you toward a personalized answer to this query, this blog will answer each of the following commonly-asked questions.

  • What material does AP Computer Science Principles cover?
  • What material does AP Computer Science A cover?
  • How do students score on the AP Computer Science Principles exam?
  • How do students score on the AP Computer Science A exam?
  • Who should take AP Computer Science Principles?
  • Who should take Computer Science A?
  • Should I take both courses?

We begin by taking a gander at the curricular offerings for each course:

What material does AP Computer Science Principles cover?

Computer Science Principles is very much a “big picture” overview of the CS universe. Unlike with Comp Sci A, teachers have the freedom to choose the programming language they utilize. Ultimately, the exam covers the following:

  • Creative development (collaboration, design, development) – 10-13%
  • Data (binary numbers, data compression/extraction) – 17-22%
  • Algorithms and Programming (variables and assignments, data abstraction, iteration, etc.)– 30-35%
  • Computer Systems and Networks (internet, fault tolerance, parallel/distributed computing) – 11-15%
  • Impact of Computing (crowdsourcing, legal/ethical concerns/bias) – 21-26%

The end-of-course exam experience differs in that Principles students must also submit digital artifacts and create a performance task administered by the teacher.

What material does AP Computer Science A cover?

AP Computer Science A is designed to cover the equivalent of a one-semester introductory college course. The primary focus is on computing skills related to programming in Java. Ultimately, students are tested on the following in the multiple-choice section:

  • Program Design and Algorithm Development (determine code segments to produce a given output) – 30-35%
  • Code Logic (determine output/value/result of program code based on initial values) – 40-45%
  • Code Testing (analyze the code for correctness, equivalence, and errors) – 12-18%
  • Documentation (describe the behavior/conditions that produced certain results) – 12-18%

A separate essay section includes four free-response questions that hit on the following five skills areas: You will be able to write program code to…

  • create objects of a class and call methods.
  • define a new type by creating a class.
  • satisfy method specifications using expressions, conditional statements, and iterative statements.
  • create, traverse, and manipulate elements in 1D array or ArrayList objects.
  • create, traverse, and manipulate elements in 2D array objects.

How do students score on the AP Computer Science Principles exam?

In 2021, only 12.4% of test-takers nailed down a “5” on the AP Computer Science Principles exam; 21.7% earned a “4,” 32.5% earned a “3,” 19.9% earned a “2,” and 13.6% scored only a “1.” The previous year, there were only 234 students worldwide who got every single question correct. Overall, students score best on questions categorized as being related to “data & information,” “internet,” and “global impact.” Students score most poorly on questions related to programming.

How do students score on the AP Computer Science A exam?

Interestingly, a greater percentage of students score better on the more difficult Comp Sci A test. An impressive 23.9% earned a “5,” 21.9% a “4,” 19.3% a “3,” 12.1% a “2,” and 22.8% a “1.” While almost one-in-five students bomb this very challenging exam, almost 50% who sat for the test earned a “4” or a “5.” This makes sense since a more self-selecting group tends to take this test than the Principles test, including just about every future attendee of MIT, Caltech, Carnegie Mellon, and other elite engineering/CS program in the country. On that note, 601 students aced every question of the test two years ago.

Who should take AP Computer Science Principles?

Those with limited-to-no coding experience can take this course without fear. Sometimes students elect to take APCSP early in high school since the math required is nothing beyond a foray into basic algebra. This is a course that every serious student should consider taking, whether or not they plan on pursuing CS beyond high school or not. In short, this class is an excellent choice for anyone with even a casual interest in computing.

Who should take Computer Science A?

Students should have excelled in an Algebra II course and/or have experience with coding prior to enrolling in this class. APCSA is a course that anyone considering a future in the engineering, design, or software development realms should absolutely take during high school. If it is offered by your high school, colleges will expect to see this on your transcript when looking to enter a variety of tech-oriented fields of study.

Should I take both courses?

According to the College Board, these courses “can be taken in any order”. If you have extensive coding experience, this is probably solid advice. If not, we would recommend starting with APCSP. Should you enjoy this overview, then continue into APCSA in a later semester/year. For more advanced students, some will tell you that Principles is not worth your valuable time, while others will recommend taking both to demonstrate your commitment to CS to competitive universities. Ultimately, if you are a top-notch CS prospect, we feel it can still be beneficial to take APSCP if you have room in your already crowded, AP-laden schedule. However, there is no need to force this course if your day is already filled with important, and also highly relevant classes like AP Physics, AP Chemistry, AP Biology, etc.

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Dave has over a decade of professional experience that includes work as a teacher, high school administrator, college professor, and independent educational consultant. He is a co-author of the books The Enlightened College Applicant (Rowman & Littlefield, 2016) and Colleges Worth Your Money (Rowman & Littlefield, 2020).