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COMPUTER-SCIENCE-J277 · Cambridge OCR GCSE (9–1)

COMPUTER-SCIENCE-J277/21

Computational Thinking, Algorithms and Programming

Computer Science · June 2023 · Variant 1

Relative difficulty

Demanding · 3.7/5

Analysis source: OCR

Analysis aligned to the official syllabus and assessment design.

Relative difficulty

3.7 / 5

Total marks

160

Duration

180 min

Most tested topic

Data Storage and Array-based Algorithms

Cohort performance

Session statistics from official examination reports

Total marks

160

Duration

180 min

Session difficulty

3.7 / 5

Key examiner messages

Top priorities from the principal examiner before you revise

1

The J277 2023 series is rated as moderately difficult (4/5 stars).

2

While Paper 1 (Computer Systems) adhered closely to expected theory across standard network, memory, and environmental themes, Paper 2 (Computational thinking, algorithms, and programming) introduced high-cognitive-load logical challenges.

3

Candidates particularly struggled with the loop trace table and the nested loop reasoning in the sorting algorithms.

Question difficulty map

How candidates performed on each question in this series

No data available in official reports

Assessment objectives

Skill and AO weighting from official examiner commentary

Knowledge & Understanding4
Application of2
Analytical / Problem Solving1

Skill weighting

Shows the skill mix this paper tested most heavily.

Knowledge & UnderstandingKnowledge &UnderstandingApplication ofApplication ofAnalytical / Problem SolvingAnalytical /Problem Solving
SkillWeightShare

  • Knowledge & Understanding

    Weight: 4100%

  • Application of

    Weight: 250%

  • Analytical / Problem Solving

    Weight: 125%

Method marks watchlist

Where working, steps, or method marks were commonly lost

No data available in official reports

Recurring mistakes across years

Themes examiners flag in multiple recent sessions for this subject

No data available in official reports

Question choice intelligence

Mean scores and popularity for optional questions (HKDSE electives)

No data available in official reports

Level exemplars

What candidate scripts at each grade level looked like

No data available in official reports

Grade & admission context

How marks relate to grade thresholds and entry standards

Report type

Examiner report — national grade boundaries and question-level commentary

Level 9

Approx. 83% of maximum mark

Level 8

Approx. 74% of maximum mark

Level 7

Approx. 66% of maximum mark

Level 6

Approx. 57% of maximum mark

Level 5

Approx. 48% of maximum mark

Level 4

Approx. 39% of maximum mark

Level 3

Approx. 29% of maximum mark

Level 2

Approx. 18% of maximum mark

Deep insights

What top candidates did

Techniques and approaches examiners rewarded in this series

No data available in official reports

Command word playbook

How to match each command word to the expected response style

programFrequency: 7

Match the expected response style for “program” questions.

DescribeFrequency: 6

State features in sequence or list observable properties — do not explain causes unless asked.

IdentifyFrequency: 12

Name or point to the specific feature asked for — avoid extra explanation.

ExplainFrequency: 5

Give reasons and link mechanism to outcome; each point needs a because/so chain.

DiscussFrequency: 1

Present multiple perspectives with evidence; balance breadth and depth.

StateFrequency: 4

Match the expected response style for “State” questions.

Time traps

Sections where candidates spent disproportionate time relative to marks

J277/02 Section B40m / 30 marks

Min per mark: 1.3

J277/02 Section A50m / 50 marks

Min per mark: 1

Syllabus traceability

Topics linked to questions and mark weighting in this session

Data storage

20 marks this session

Additional programming techniques

16 marks this session

Ethical, legal, cultural and environmental impact

14 marks this session

MCQ trap analytics

Commonly chosen wrong options from examiner commentary

No data available in official reports

Topic heatmap across years

Mark concentration by topic and exam year for this subject

Mark intensity

LowHigh
Topic
2022
2023
2024
Σ

Data storage

18
20
16
54

Designing, creating and refining algorithms

25
—
20
45

Wired and wireless networks, protocols and layers

18
—
—
18

Additional programming techniques

—
16
—
16

Ethical, legal, cultural and environmental impact

—
14
—
14

Defensive design

—
—
12
12

Paper comparison

Marks and duration breakdown across papers in this session

J277/01 Computer Systems: J277/02 Computational thinking, algorithms and programming:

80 marks90 min

Marks you can still earn

Where valid approaches outside the mark scheme may still gain credit

No data available in official reports

Practise what examiners flagged

Target weak topics from this report inside the Revui app

Data storage

20 marks this session

Practise in Revui

Additional programming techniques

16 marks this session

Practise in Revui

Ethical, legal, cultural and environmental impact

14 marks this session

Practise in Revui

Self-diagnostic checklist

Key actions before you sit this paper — copy and tick off as you revise

  • 1Message

    The J277 2023 series is rated as moderately difficult (4/5 stars).

  • 2Message

    While Paper 1 (Computer Systems) adhered closely to expected theory across standard network, memory, and environmental themes, Paper 2 (Computational thinking, algorithms, and programming) introduced high-cognitive-load logical challenges.

  • 3Message

    Candidates particularly struggled with the loop trace table and the nested loop reasoning in the sorting algorithms.

Teacher briefing pack

One-page session summary for tutors and classroom review

June 2023 2023

Computer Science

The J277 2023 series is rated as moderately difficult (4/5 stars). While Paper 1 (Computer Systems) adhered closely to expected theory across standard network, memory, and environmental themes, Paper 2 (Computational thinking, algorithms, and programming) introduced high-cognitiv

  • The J277 2023 series is rated as moderately difficult (4/5 stars).

  • While Paper 1 (Computer Systems) adhered closely to expected theory across standard network, memory, and environmental themes, Paper 2 (Computational thinking, algorithms, and programming) introduced high-cognitive-load logical challenges.

  • Candidates particularly struggled with the loop trace table and the nested loop reasoning in the sorting algorithms.

Total marks
160
Duration
180 min
Session difficulty
3.7 / 5

Session analysis

The J277 2023 series is rated as moderately difficult (4/5 stars). While Paper 1 (Computer Systems) adhered closely to expected theory across standard network, memory, and environmental themes, Paper 2 (Computational thinking, algorithms, and programming) introduced high-cognitive-load logical challenges. Candidates particularly struggled with the loop trace table and the nested loop reasoning in the sorting algorithms.

Updated Jun 14, 2026

Paper breakdown

J277/01 Computer Systems: J277/02 Computational thinking, algorithms and programming:

80 marks90 min

Top chapters

Data storage20 marks
Additional programming techniques16 marks
Ethical, legal, cultural and environmental impact14 marks

Exam structure insights

Marks by chapter

See where the marks were concentrated so revision time goes to the highest-value topics.

Data storage20 marks
Additional programming techniqu16 marks
Ethical, legal, cultural and en14 marks
Designing, creating and refinin13 marks
Wired and wireless networks, pr12 marks
Programming fundamentals12 marks
Searching and sorting algorithms8 marks
Networks and topologies7 marks

Mark accessibility

Estimate which marks were basic, mid-level, or high-difficulty.

75% within easy or medium reach

48
72
40
Easy: 48 marksMedium: 72 marksHard: 40 marks

Command word frequency

Spot common command words so answers match the expected response style.

program7 times
Describe6 times
Identify12 times
Explain5 times
Discuss1 times
State4 times

Question type mix

Compare the mark share of each paper section and question type.

160Marks

  • Short Answer / Fill-in / Multiple Choice

    58·32·36%

  • Program Writing / SQL / Pseudocode

    54·9·34%

  • Long Answer / Analysis

    25·6·16%

  • Algorithms / Logical Diagram Drawing

    23·7·14%

Study ROI

Bigger bubbles recur more often; higher bubbles carry more marks, helping you rank revision priorities.

Difficulty →Recurrence % →Ethical, legal, cu…Designing, creatin…Data storageWired and wireless…

Difficulty trend

Compare difficulty across recent years.

3.220223.72023

Time vs marks

Compare marks with suggested time allocation to plan exam pacing.

MarksMinutesMarks / min

J277/02 Section A

1.00 m/min
50
50

J277/02 Section B

0.75 m/min
30
40

Total marks

80

Total time

90 min

Avg pace

0.89

Next-year prediction

Topics worth watching next year, with the reason shown directly below each bar.

Architecture of the CPU

95%

95%

CPU performance

88%

88%

Threats to computer systems and networks

80%

80%

Difficulty Verdict

The J277 2023 series is rated as moderately difficult (4/5 stars). While Paper 1 (Computer Systems) adhered closely to expected theory across standard network, memory, and environmental themes, Paper 2 (Computational thinking, algorithms, and programming) introduced high-cognitive-load logical challenges. Candidates particularly struggled with the loop trace table and the nested loop reasoning in the sorting algorithms.

Where the Marks Are

The heaviest mark concentration lies in Programming Fundamentals and Designing, Creating and Refining Algorithms. Practical coding tasks and array manipulation accounted for over 30% of the total marks. High-tariff areas included:

Exam tips

Paper format

Duration
1h 30min
Total marks
80
Weighting
50%
Question types
Short Answer & Program Logic MCQs, Structured Code & Circuit Drawing, Algorithm Writing & Scenario Solutions

Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.

COMPUTER-SCIENCE-J277/21 — Cambridge OCR GCSE (9–1) Computer Science (June 2023) | Revui