What is the AP CSP exam format?

The AP Computer Science Principles exam has exactly two scored components, and understanding how each is weighted changes your study priorities immediately.

The Multiple Choice section contains 70 questions and runs for 120 minutes. Questions fall into two types: single-select (one correct answer) and multi-select (two correct answers — both must be chosen for credit). Multi-select questions trip up students who rush, so flag them as you go.

The Create Performance Task is completed during class time over approximately 12 hours across several weeks. You write a program, then submit a video of it running and written responses explaining your design choices. College Board readers score it using a 6-row rubric — each row is worth 1 point.

One thing most guides don’t tell you: the MC section includes questions that reference a shared stimulus — a block of pseudocode or a data scenario that two or three questions refer to. Treat these like a reading comprehension passage. Read the stimulus carefully once, then answer all linked questions before moving on.

How does the Create Performance Task work?

The Create Task is worth 30% of your score, and it is the part most students underestimate. You build a program of your choice, record a short video of it running, and write responses to specific prompts that map directly to the 6-row scoring rubric.

Here are the six rubric rows you must address:

1. Program purpose and function — describe what your program does and demonstrate it in the video.
2. Data abstraction — show a list (array) being used to manage complexity; explain how it stores data.
3. Managing complexity — explain how your list manages complexity that would be harder without it.
4. Procedural abstraction — show a student-developed procedure (function) with a parameter.
5. Algorithm implementation — your procedure must include sequencing, selection, and iteration.
6. Testing — describe two different test calls with different arguments and explain the results.

In my experience reviewing student submissions, Row 3 (managing complexity) is the most commonly missed. Students list an array but never explain why a list is better than individual variables for their specific use case. One sentence of genuine justification earns that point.

What are the five Big Ideas tested on AP CSP?

Every question on the AP CSP exam maps to one of five Big Ideas. Knowing which Big Idea a question targets helps you apply the right mental framework fast.

• 🎨 Big Idea 1 — Creative Development (CRD): How programs are designed collaboratively, iteratively, and with clear documentation.
• 📊 Big Idea 2 — Data (DAT): How data is stored, compressed, analysed, and used to draw conclusions. Includes binary, lossless vs. lossy compression, and metadata.
• 🔁 Big Idea 3 — Algorithms and Programming (AAP): The largest section. Covers variables, lists, procedures, Boolean logic, iteration, and the College Board pseudocode notation.
• 🌐 Big Idea 4 — Computer Systems and Networks (CSN): How the internet works — IP addresses, DNS, HTTP, fault tolerance, and parallel vs. sequential computing.
• 🌍 Big Idea 5 — Impact of Computing (IOC): Privacy, security, bias in algorithms, intellectual property, and the digital divide.

Multiple choice vs. Create Task: a side-by-side comparison

Understanding how the two components differ — and what each rewards — lets you allocate study time strategically.

How do you study effectively for AP CSP?

Effective AP CSP prep follows a specific sequence. Here is the six-step plan I recommend to every student I work with.

1. Audit the Big Ideas. Take one released practice exam under timed conditions. Score it, then tag every wrong answer to its Big Idea. This gives you a personal weakness map in under 3 hours.
2. Start the Create Task early. Begin at least 3 weeks before the submission deadline. The biggest scoring mistakes happen when students rush the written responses in the final 48 hours.
3. Master pseudocode notation. College Board uses its own pseudocode (not Python, not Java). Practice reading it daily for 10 minutes. Translate pseudocode to plain English, then back. This skill alone can add 5–8 correct answers.
4. Review IOC concepts. Spend at least 2 focused hours on Big Idea 5 — privacy laws, algorithmic bias, the digital divide, and Creative Commons licensing. These questions are pure reading comprehension once you know the vocabulary.
5. Simulate exam conditions. One week before the exam, take a full 120-minute timed practice run with no notes and no phone. Review results the next morning.
6. Use the College Board rubric as a checklist. Before submitting your Create Task, read each rubric row and verify your written response addresses it explicitly. If you can’t point to the sentence that earns each point, rewrite it.

How to read AP CSP pseudocode (worked example)

AP CSP uses College Board’s own pseudocode notation, and it appears in roughly 30–40% of MC questions. Students who can read it fluently have a significant time advantage.

Here is a real-style pseudocode problem and a step-by-step walkthrough:

PROBLEM: What does this procedure return when called with n = 4?

PROCEDURE mystery(n)
{
    total ← 0
    i ← 1
    REPEAT UNTIL (i > n)
    {
        IF (i MOD 2 = 0)
        {
            total ← total + i
        }
        i ← i + 1
    }
    RETURN total
}

TRACE:
  i=1: 1 MOD 2 = 1  → not 0 → skip   | total = 0
  i=2: 2 MOD 2 = 0  → add 2           | total = 2
  i=3: 3 MOD 2 = 1  → skip            | total = 2
  i=4: 4 MOD 2 = 0  → add 4           | total = 6
  i=5: 5 > 4 → LOOP ENDS

ANSWER: mystery(4) returns 6
WHY: The procedure sums all EVEN numbers from 1 to n.
  

The key technique here is variable tracing — tracking the value of each variable at every step. Write it out in a small table on your scratch paper. Students who trace variables correctly almost never miss pseudocode questions.

Common mistakes that cost students points on AP CSP

After reviewing hundreds of student practice tests, I see the same errors repeatedly. Here are the most costly ones — and how to fix them.

• 🚫 Confusing “undecidable” with “inefficient.” An undecidable problem has no algorithm that always gives a correct yes/no answer (e.g., the Halting Problem). An inefficient problem just takes a long time. These are tested as distinct concepts — don’t mix them up.
• 🚫 Misreading multi-select questions. Multi-select questions say “select TWO answers.” Students who select only one get zero credit. Always re-read the question stem before moving on.
• 🚫 Treating lossless and lossy compression as interchangeable. Lossless compression (e.g., ZIP) allows perfect reconstruction. Lossy compression (e.g., JPEG, MP3) permanently discards data. The exam tests whether you know which is appropriate for a given scenario.
• 🚫 Ignoring the Create Task video. Your video must show the program running and producing output. A video that only shows code — not execution — fails Row 1 automatically.
• 🚫 Using “and” when “or” is correct in Boolean logic. “The condition is true if x > 5 AND x < 10" is different from "OR." Draw a number line when Boolean logic questions appear.

Reveal-on-click practice problems

Work through each problem on your own first, then click to reveal the full solution and explanation.

x ← 7
IF (x MOD 2 = 0)
{
    DISPLAY "even"
}
ELSE
{
    DISPLAY "odd"
}
    

Frequently asked questions about the AP CSP practice exam