AP Computer Science Principles exam technique: the Create performance task and the end-of-course multiple-choice exam, including reading AP CSP pseudocode and writing the required responses

What the AP CSP assessment actually demands

AP Computer Science Principles is assessed in two ways that need two different skills. The Create performance task (30%) is completed during the course: you build a program and document it well, in program code, a video, and written responses. The end-of-course exam (70%) is a multiple-choice exam of about 70 questions in 2 hours, covering all five Big Ideas, mixing pseudocode tracing with conceptual questions about data, systems and impact. This guide builds both skills and drills the traps the College Board repeats.

The matching dot-point pages each have their own worked exam questions: collaboration, program function and purpose, variables and assignments, iteration, and developing procedures and libraries.

The Create performance task

You design and develop a program of your own choosing and submit three things: the program code, a video showing it run (with input and output), and written responses. The written responses are where most marks are won or lost, so plan them deliberately.

The responses must cover:

1. Purpose and function. State the problem the program solves and how a user interacts with it, naming at least one input and one output.
2. Development. Describe how you developed the program iteratively, including a difficulty and how you resolved it (through collaboration or testing and refinement). Be specific about what changed.
3. A selected algorithm. Identify an algorithm that is fundamental to your program and explain how it works, ideally one built from sequencing, selection and iteration.
4. A selected procedure. Identify a procedure with a parameter that affects its result, and explain how the procedure manages complexity through abstraction.
5. Testing. Describe how you tested the program, naming specific inputs and the expected output for each, including an edge case.

A recurring rule: anything you did not create (code, images, media) must be appropriately licensed and acknowledged. Plagiarism breaks the task.

Reading AP CSP pseudocode

Many multiple-choice questions show a pseudocode segment and ask what it displays or returns. Trace it by hand:

1. Make a variable table. Write each variable's name and current value; update it one statement at a time.
2. Evaluate the right side of each assignment first, then store it (the arrow stores; it is not equality).
3. Apply the AP CSP conventions. MOD is the remainder; lists are 1-indexed; REPEAT n TIMES runs a fixed number of times; REPEAT UNTIL runs until its condition becomes true (so it checks the condition each pass).
4. Record every output exactly. For each DISPLAY, write what is shown.

Writing pseudocode in responses

The Create task and some practice questions ask you to write or explain pseudocode. A dependable routine:

1. Plan the steps (sequencing), decisions (selection) and repetition (iteration).
2. Use a list when handling a collection, and iterate with FOR EACH or a counted REPEAT.
3. Wrap reusable logic in a PROCEDURE with parameters and a RETURN, which demonstrates abstraction.
4. Initialise accumulators (0 for sums, 1 for products) before loops, and guard against errors like dividing by zero.

The traps the College Board repeats

These appear across the exam. Internalise them.

• 1-indexed lists. list[1] is the first element, not list[0]. The 0-based answer is the trap.
• MOD versus division. 17 MOD 5 is the remainder (2), not the quotient (3).
• Boolean operator order. Evaluate relational comparisons first, then NOT, then AND, then OR.
• Correlation versus causation. Two things changing together does not prove one causes the other.
• Both sides of impact. Impact questions want both benefits and harms, and intended versus unintended effects, not a one-sided answer.

Check your knowledge

A mix of pseudocode-tracing, conceptual and Create-task questions covering all five Big Ideas. Attempt them under timed conditions, then check against the solutions.

1. For the list vals ← [3, 6, 9, 12], what is vals[3]? (1 mark)
2. What does 23 MOD 7 evaluate to? (1 mark)
3. State the value of (NOT (2 > 5)) AND (4 = 4). (2 marks)
4. After x ← 5 and then x ← x * 3 - 2, what is x? (1 mark)
5. How many times does the body of REPEAT 5 TIMES { ... } run? (1 mark)
6. In one sentence, what must a Create task written response include when describing the program's purpose and function? (2 marks)
7. Explain why "ice cream sales and sunburns both rise together" does not prove one causes the other. (2 marks)
8. Give one beneficial and one harmful effect of a navigation app, labelling which is intended. (2 marks)