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The Tian2 Study Library AP Edition · Tian2 Editorial Bureau
Volume I · MMXXVI AP Computer Science Principles
Library Catalogue AP Computer Science Principles
⁂   Computer Science · AP Exam

Computer Science
Principles Study Library.

Expert-authored study guides covering the five Big Ideas of AP CSP — creative development, data, algorithms and programming, computer systems and networks, and the impact of computing — plus a complete Create Performance Task guide.

5 Big Ideas 70 MCQ + Create Task 180 min end-of-course 175,174 candidates (2025)
End-of-Course Exam 180 minutes · 70 MCQ + Written Response
MCQ Weight 70% 70 questions · 120 minutes
Create Task 30% Through-course · 9 hrs in-class · 6-row rubric
Score Scale 1–5 61.9% scored 3+ (2025) · Mean: 2.87
Exam Structure

Two-component assessment.

Component 1: End-of-Course Exam (70%)

Section I MCQ (120 min): 70 questions — 57 single-select, 5 single-select with reading passage (computing innovation), and 8 multiple-select (choose 2 correct answers). No calculator. AP pseudocode reference sheet provided.

Section II Written Response (60 min): 4 prompts about your own Create Performance Task program — WR1, WR2(a), WR2(b), WR2(c). You bring your Personalized Project Reference (PPR); no other notes. Max 850 words total written response.

Component 2: Create Performance Task (30%)

Submitted through AP Digital Portfolio approximately 2 weeks before exam day (2026 deadline: April 30). Approximately 9 in-class hours.

Deliverables: a complete program in any language (Python, JavaScript, Scratch, App Inventor, etc.) + a 60-second video showing input/functionality/output + a Personalized Project Reference (PPR) with two code segment screenshots. Scored on a 6-row rubric (6 points total).

Score Distributions (2025)

5
10.7%
4
19.9%
3
31.2%
2
21.4%
1
16.8%

n = 175,174 · Mean: 2.87 · Only ~31% scored 4 or 5. The mean below 3 reflects the course's broad, heterogeneous population — AP CSP is designed to broaden CS participation, attracting many first-time CS students.

Curriculum — Five Big Ideas

Study by unit.

1.
Creative Development
Collaboration in program development · Input and output specifications · Iterative development process · Debugging: syntax errors, logic errors, runtime errors · Documentation and code comments · Program purpose vs. program function distinction
Big Idea 1
10–13% of exam
Study unit ›
2.
Data
Binary representation: bits, bytes, binary-to-decimal conversion · Data types in binary (integers, floating point, text) · Analog vs. digital; sampling rate and resolution · Lossless vs. lossy compression · Metadata and privacy implications · Extracting patterns, trends, and insights from data · Data visualization and analysis · Correlation vs. causation · Limitations of data: incomplete data, biased samples · Analog-to-digital conversion
Big Idea 2
17–22% of exam
Study unit ›
3.
Algorithms and Programming
AP pseudocode: variables (), arithmetic, relational operators, Boolean (AND, OR, NOT) · Lists: INSERT, APPEND, REMOVE, LENGTH, 1-based indexing · Procedures with parameters; RETURN values · Sequential, selection (IF/ELSE), and iteration (REPEAT N TIMES, REPEAT UNTIL, FOR EACH) · Linear search vs. binary search (binary requires sorted list) · Algorithm efficiency: conceptual time comparison · Heuristics for intractable problems · Undecidable problems and the Halting Problem · Simulations and modeling
Big Idea 3
30–35% of exam
Study unit ›
4.
Computer Systems and Networks
The Internet: packet switching and routing · TCP/IP protocol suite · DNS: domain names to IP addresses · HTTP and HTTPS: request-response model · Fault tolerance and redundant paths · Parallel computing: tasks across multiple processors · Distributed computing: tasks across multiple computers · Bandwidth and throughput · Symmetric encryption · Public-key (asymmetric) encryption: public key encrypts, private key decrypts · Digital certificates and certificate authorities · Cybersecurity attacks: phishing, malware, DDoS
Big Idea 4
11–15% of exam
Study unit ›
5.
Impact of Computing
Beneficial and harmful effects of computing innovations · Digital divide: unequal access by geography, income, age · Bias in algorithms and training data · Crowdsourcing · Copyright, Creative Commons, and open source licensing · Intellectual property and software piracy · Privacy: data collection, ownership, and surveillance · Computing and civil liberties: freedom of expression and censorship · Cybersecurity ethics and computing-related laws · Safety, security, and authentication
Big Idea 5
21–26% of exam
Study unit ›
CPT
Create Performance Task — Complete Guide
6-row rubric (1 pt each): Program Purpose and Function · Data Abstraction · Managing Complexity · Procedural Abstraction · Algorithm Implementation · Testing · Written Response: WR1 (Purpose), WR2(a) (Algorithm), WR2(b) (Errors and Testing), WR2(c) (Data and Procedural Abstraction) · PPR screenshots · 850-word maximum · AP Digital Portfolio submission
Through-course
30% of score
Study unit ›
Create Performance Task

The 6-row rubric, explained.

Each row earns 0 or 1 point. The rows are graded independently — strong evidence in Row 5 does not compensate for missing evidence in Row 3. Every row must be satisfied on its own merits.

Row
Criterion
What earns the point
1
Program Purpose and Function
Video shows input, the program running, and output. Written response describes what the program does (function) AND why it was created (purpose). Must distinguish purpose from function.
2
Data Abstraction
PPR screenshot shows a list (or other collection) storing multiple elements of the same type. Written response explains what the data in the list represents.
3
Managing Complexity
Written response explains why the list is necessary — i.e., the program could not function as well or at all without the list. Must explain logical necessity, not just convenience.
4
Procedural Abstraction
PPR screenshot shows a student-defined procedure with at least one parameter. Written response explains how the parameter affects the procedure's behavior.
5
Algorithm Implementation
The student-defined procedure (from Row 4) must contain all three: sequencing, selection, AND iteration — all within the same procedure body. Written response explains the algorithm.
6
Testing
Two test cases documented with: specified conditions/inputs, expected result, actual result, and an error identified and corrected. The two test cases must produce different expected results.
Quick Reference

AP Pseudocode essentials.

The pseudocode reference sheet is provided during MCQ. You must still be fluent with these constructs to work quickly under time pressure.

Variables and Assignment

x ← 5
y ← x + 3
DISPLAY(y)  → 8

a ← "hello"
INPUT(name)

Lists (1-based index)

nums ← [3, 1, 4, 1, 5]
APPEND(nums, 9)
INSERT(nums, 2, 7)
REMOVE(nums, 1)
LENGTH(nums) → 5
nums[1] → first element

Procedures

PROCEDURE add(a, b)
{
  RETURN a + b
}
result ← add(3, 4)
DISPLAY(result)  → 7

Selection

IF (condition)
{
  <statements>
}
ELSE
{
  <statements>
}

Iteration

REPEAT 5 TIMES
{  <statements> }

REPEAT UNTIL (x = 0)
{  <statements> }

FOR EACH item IN list
{  <statements> }

Key Distinctions

  • Binary search requires a sorted list; linear does not
  • Symmetric: same key to encrypt and decrypt
  • Asymmetric: public key encrypts, private key decrypts
  • Undecidable: Halting Problem — no algorithm can solve for all inputs
  • AND / OR / NOT (not && / || / !)
Study Intelligence

High-frequency MCQ topics.

Algorithms unit (30–35%) dominates the exam

More than a third of MCQ questions come from algorithms and programming. Master list operations, procedure tracing, and pseudocode reading. Know binary vs. linear search and when each applies.

Impact of Computing (21–26%) — opinion free

These questions have objectively correct answers based on definitions — digital divide, bias in algorithms, privacy, copyright. Study the precise definitions (e.g., Creative Commons vs. copyright vs. open source).

Data unit: binary and compression

Overflow error (number too large for bits allocated) vs. roundoff error (floating-point precision). Lossless (exact reconstruction) vs. lossy (reduced quality; cannot be undone). Know that metadata can reveal private information even without accessing the content.

Networks: encryption and the Internet

The Internet's redundant paths enable fault tolerance — data can reroute when a node fails. HTTPS = HTTP + TLS encryption. Public-key encryption: the sender uses the recipient's public key to encrypt; only the recipient's private key can decrypt. Certificate authorities verify public key ownership.

Our worked solutions and practice questions are original instructional content created by Tian2 AP. They are aligned to the concepts and skills described in College Board’s Course and Exam Description and are not reproductions of, or affiliated with, College Board’s official materials.