IB DP Computer Science B.1: Computational Thinking

B.1 Computational thinking is the first sub-topic of Theme B, “Computational thinking and problem-solving”, in the IB Diploma Programme Computer Science course first assessed in 2027. The IB subject brief describes computational thinking as a four-part process: specifying problems and success criteria, decomposing them, abstracting and generalizing them, and testing and evaluating solutions. It is assessed on Paper 2 and underpins the whole course, including the internal assessment.

Scope of this page. This is an overview written only from the IB’s public Diploma Programme Subject Brief, Sciences: Computer science, first assessment 2027 (© International Baccalaureate Organization 2024). The detailed learning outcomes for B.1 are set out in the full DP Computer Science guide, available to IB schools through the Programme Resource Centre. Use your school’s copy of the full guide for the exact content and depth.

What does the IB subject brief say computational thinking involves?

The brief states that computational thinking involves the ability to:

1. Specify problems in terms of their computational context and determine success criteria.
2. Decompose complex real-world problems into more manageable problems.
3. Abstract problems and generalize them to enable algorithmic thinking and to develop solutions.
4. Test and evaluate solutions for improvements.

The brief also says the course “is underpinned by the computational thinking process” and that it develops “skills in algorithmic thinking and computer programming”.

How much time does B.1 get?

The brief’s recommended teaching hours are 5 hours at SL and 5 hours at HL, the same at both levels. That is small compared with B.2 Programming (40 SL / 42 HL), because B.1 is a way of working that is then applied throughout the other sub-topics rather than a large body of separate content.

Theme B sub-topic	SL hours	HL hours
B.1 Computational thinking	5	5
B.2 Programming	40	42
B.3 Object oriented programming (OOP)	7	23
B.4 Abstract data types (HL only)	0	23

Where is B.1 assessed?

According to the brief:

• Paper 2 has questions for SL and HL on the three topics in Theme B, “Computational thinking and problem-solving”. Paper 2 is 1 hour 15 minutes (35%) at SL and 2 hours (40%) at HL. Some questions require programming, with equivalent Java and Python versions.
• The computational solution (internal assessment) asks students to develop a computational solution to a real-world problem of their own choosing, using “the computational thinking process”. It is 35 hours of teaching time and is worth 30% at SL and 20% at HL.

Assessment Objective 4 in the brief is to “demonstrate the application of computational thinking skills to solve real-world problems using computer science solutions”, and Assessment Objective 3 includes constructing and evaluating “problem specifications, system requirements, success criteria, testing strategies, and programs”.

How do the four parts fit together?

The brief lists the four abilities in an order that works as a cycle for any problem:

• Specify first: say what the problem is, in computing terms, and how you will know a solution has succeeded (success criteria). These criteria are what testing and evaluation later check against.
• Decompose next: split a large real-world problem into smaller problems that can each be solved.
• Abstract and generalize: focus on what matters for the solution and express it in a general form, so that an algorithm can be designed.
• Test and evaluate: check the solution against the success criteria and look for improvements, which may send you back to an earlier step.

The same cycle is what the brief describes for the internal assessment: “identify a problem or unanswered question, and design, develop and evaluate a proposed solution”.

How should you revise B.1?

• Learn the four parts in the brief’s own words, and be able to explain each one in a sentence with an example from a problem you have programmed.
• Practise writing success criteria that can be tested: measurable statements, not vague aims.
• Apply the process every time you write a program for B.2, B.3 and (at HL) B.4, because Paper 2 questions on Theme B draw on it.
• Check the full DP guide for the exact B.1 learning outcomes and command terms your teacher will use.

Frequently asked questions

Is B.1 the same at SL and HL? The brief gives the same recommended hours, 5 at SL and 5 at HL. Any difference in depth would be shown in the full guide.

What are success criteria? In the brief’s first ability, they are what you determine when you specify a problem: the conditions a solution must meet to count as successful, which testing and evaluation then check.

Which paper examines computational thinking? Paper 2 covers Theme B, which includes B.1. The process is also central to the internal assessment.

Can I learn B.1 separately from programming? It is better not to. The brief says the whole course is underpinned by the computational thinking process, so it should be used whenever you design a program.

Related pages

• B.1 Computational thinking revision notes
• B.1 Computational thinking practice questions
• B.2 Programming study guide
• DP Computer Science syllabus guide

Source

International Baccalaureate Organization, Diploma Programme Subject Brief, Sciences: Computer science, first assessment 2027 (© 2024), sections I to III. The complete subject guide is available through the IB Programme Resource Centre.