12. Software Development
Program development life cycle, program design tools, program testing, test data and maintenance.
Statometer40RegularNext Paper 258%Everything for this topic — study hub
AS Level · 9618 · Paper 2
Statometer — what 33 real papers say about this topic and each of its 4 syllabus bullets
Regular · #12 of 12 in AS Level · recomputed with every new session
Comes up most sessions for a few marks — know the definitions and one worked example.
- Next Paper 2
- 58%
- 6 in 10 chance it is set
- Marks a paper
- 7.6 / 75
- 10% of Paper 2 · fair share 25%
- Appeared in
- 18 / 33
- Paper 2 sittings 2021–2026
- Last set
- May/Jun 2026
- 9618/23 · Q3 · 11 marks · 4-series streak
What the papers say
- Set in 18 of 33 Paper 2 sittings — it rotates in and out, so it is a gamble to skip.
- Worth about 7.6 marks a paper (10% of Paper 2, well under its fair share of 25%).
- Last set May/Jun 2026 · 9618/23 · Q3 for 11 marks — in the most recent series.
- Set in each of the last 4 series without a miss.
- Rising: about 5.9 marks a paper in the earlier years, 9.3 in the latest.
- Lives on “Complete” and “Identify” — 96% of its questions: you must produce something — code, a diagram, a table — practise doing it, not reading it.
- 79% of its questions involve a diagram, table or figure — practise with pen and paper.
- 67% of its questions are set out as code, pseudocode or a table to complete.
- Its biggest question so far: 27 marks (May/Jun 2026 · 9618/22 · Q1).
- Inside the topic, §12.1 Program development life cycle carries the most marks (33%) and §12.3 Program maintenance the least (6%).
- It is examined almost entirely as AO2 (Apply & analyse, 88%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
- The examiner has commented on 13 of its questions — read “What the examiner said” before you practise.
Command words
Share of questions using the word (a question can use several). What each wants →
Question shapes
- ≤ 6 mk6
- 7–9 mk7
- 10–12 mk7
- 13–15 mk3
- 16+ mk1
Average 9.4 marks a question · 79% with a figure or table · 67% with code · biggest 27 marks
Assessment objectives — how it is examined
Every part of every current-syllabus question filed under Cambridge's AO1 / AO2 / AO3 (from its command word and what it asks you to do), so you know whether this topic pays for definitions, for applying, or for judging and building.
- AO1 Knowledge & understanding
- AO2 Apply & analyse
- AO3 Design, program & evaluate
Paper 2 as a whole
| Paper 2 | Syllabus | Measured |
|---|---|---|
| AO1 Knowledge & understanding | 0% | 0% |
| AO2 Apply & analyse | 40% | 46% |
| AO3 Design, program & evaluate | 60% | 54% |
Syllabus = Cambridge's grid; measured = the bank's current-syllabus papers.
Inside the topic — every syllabus bullet, measured
Each part of each question is filed under the bullet it examines; the numbers are per Paper 2 sitting, exactly like the topic's. Open a bullet for its own Statometer.
12.1Program development life cycle#9 of 14 on Paper 2Regular · 3949% next paper2.6 marks14/33 sittings↗ May/Jun 2026Regular · 3949%
2.6 · 33% of topic14/33May/Jun 2026latest series · ↗Set most sessions for a few marks; know the definition and one example.Syllabus: its purpose; waterfall, iterative and RAD models with their principles, benefits and drawbacks; the analysis, design, coding, testing and maintenance stages
- Next Paper 2
- 49%
- 2 in 4
- Marks a paper
- 2.6
- 3% of the paper · 33% of the topic
- Asked in
- 14 / 33
- Paper 2 sittings · 16 questions
- Last asked
- May/Jun 2026
- 9618/23 · Q3 · 9.5 marks · 4-series streak
- Asked in 14 of 33 Paper 2 sittings — roughly one paper in 2.
- About 2.6 marks a paper (3% of Paper 2; 33% of the topic's marks across its 4 bullets).
- Last asked May/Jun 2026 · 9618/23 · Q3 (9.5 marks) — in the most recent series.
- Asked in each of the last 4 series.
- Rising: 1 → 3.8 marks a paper.
- Usually “Complete” or “Identify”: you must produce something — code, a diagram, a table — practise doing it, not reading it.
- Biggest chunk of marks so far: 9.5 in May/Jun 2026 · 9618/23 · Q3.
- It is examined almost entirely as AO2 (Apply & analyse, 88%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
Last 12 sittings↗ RisingAssessment objectives
AO2 88%- AO1 Knowledge & understanding
- AO2 Apply & analyse
- AO3 Design, program & evaluate
- Complete81%
- Identify81%
- State63%
- Give19%
12.2Program design#10 of 14 on Paper 2Occasional · 3037% next paper2 marks11/33 sittings→ May/Jun 2026Occasional · 3037%
2 · 33% of topic11/33May/Jun 2026latest series · →Rotated in occasionally — the bullet students skip and then meet.Syllabus: structure charts (purpose, construction, parameters between modules, deriving pseudocode) and state-transition diagrams
- Next Paper 2
- 37%
- 1 in 4
- Marks a paper
- 2
- 3% of the paper · 33% of the topic
- Asked in
- 11 / 33
- Paper 2 sittings · 15 questions
- Last asked
- May/Jun 2026
- 9618/23 · Q3 · 1.5 marks · 4-series streak
- Asked in 11 of 33 Paper 2 sittings — roughly one paper in 3.
- About 2 marks a paper (3% of Paper 2; 33% of the topic's marks across its 4 bullets).
- Last asked May/Jun 2026 · 9618/23 · Q3 (1.5 marks) — in the most recent series.
- Asked in each of the last 4 series.
- Usually “Complete” or “Identify”: you must produce something — code, a diagram, a table — practise doing it, not reading it.
- Biggest chunk of marks so far: 10 in May/Jun 2026 · 9618/22 · Q1.
- It is examined almost entirely as AO2 (Apply & analyse, 87%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
Last 12 sittings→ SteadyAssessment objectives
AO2 87%- AO1 Knowledge & understanding
- AO2 Apply & analyse
- AO3 Design, program & evaluate
- Complete87%
- Identify60%
- State53%
- Give20%
12.3Program testing#11 of 14 on Paper 2Occasional · 3041% next paper1.8 marks12/33 sittings→ May/Jun 2026Occasional · 3041%
1.8 · 29% of topic12/33May/Jun 2026latest series · →Rotated in occasionally — the bullet students skip and then meet.Syllabus: syntax, logic and run-time errors; dry run, walkthrough, white-box, black-box, integration, alpha, beta, acceptance and stub testing; test plans; normal/abnormal/extreme data
- Next Paper 2
- 41%
- 2 in 4
- Marks a paper
- 1.8
- 2% of the paper · 29% of the topic
- Asked in
- 12 / 33
- Paper 2 sittings · 14 questions
- Last asked
- May/Jun 2026
- 9618/22 · Q1 · 12 marks · 4-series streak
- Asked in 12 of 33 Paper 2 sittings — roughly one paper in 3.
- About 1.8 marks a paper (2% of Paper 2; 29% of the topic's marks across its 4 bullets).
- Last asked May/Jun 2026 · 9618/22 · Q1 (12 marks) — in the most recent series.
- Asked in each of the last 4 series.
- Usually “Complete” or “Identify”: you must produce something — code, a diagram, a table — practise doing it, not reading it.
- Biggest chunk of marks so far: 12 in May/Jun 2026 · 9618/22 · Q1.
- It is examined almost entirely as AO2 (Apply & analyse, 82%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
Last 12 sittings→ SteadyAssessment objectives
AO2 82%AO3 19%- AO1 Knowledge & understanding
- AO2 Apply & analyse
- AO3 Design, program & evaluate
- Complete86%
- Identify64%
- State36%
- Explain14%
12.3Program maintenance#14 of 14 on Paper 2Occasional · 815% next paper0.3 marks4/33 sittings→ May/Jun 2025Occasional · 815%
0.3 · 6% of topic4/33May/Jun 20252 series ago · →Rotated in occasionally — the bullet students skip and then meet.Syllabus: perfective, adaptive and corrective maintenance; analysing and amending an existing program
- Next Paper 2
- 15%
- 1 in 5 or less
- Marks a paper
- 0.3
- 0% of the paper · 6% of the topic
- Asked in
- 4 / 33
- Paper 2 sittings · 4 questions
- Last asked
- May/Jun 2025
- 9618/22 · Q1 · 4 marks · 2 series ago
- Asked in only 4 of 33 Paper 2 sittings — rare, which is exactly why it catches candidates out.
- About 0.3 marks a paper (0% of Paper 2; 6% of the topic's marks across its 4 bullets).
- Last asked May/Jun 2025 · 9618/22 · Q1 (4 marks), 2 seriess ago.
- Usually “State” or “Give”: short, precise answers in syllabus words.
- Biggest chunk of marks so far: 4 in May/Jun 2025 · 9618/22 · Q1.
- It is examined almost entirely as AO2 (Apply & analyse, 95%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
Last 12 sittings→ SteadyAssessment objectives
AO2 95%- AO1 Knowledge & understanding
- AO2 Apply & analyse
- AO3 Design, program & evaluate
- State75%
- Give50%
- Complete50%
- Identify50%
16% of the topic's marks sit in question parts that belong to another topic (scenario questions cross sections) or that no bullet claims; they count for the topic, not for a bullet.
Marks a paper, year by year
By exam series
- May/Jun9/18 · 6.4 mk
- Oct/Nov9/15 · 7.3 mk
What you need to know4syllabus §12.1, §12.2, §12.3
- 12.1Program development life cycle — its purpose; waterfall, iterative and RAD models with their principles, benefits and drawbacks; the analysis, design, coding, testing and maintenance stages
- 12.2Program design — structure charts (purpose, construction, parameters between modules, deriving pseudocode) and state-transition diagrams
- 12.3Program testing — syntax, logic and run-time errors; dry run, walkthrough, white-box, black-box, integration, alpha, beta, acceptance and stub testing; test plans; normal/abnormal/extreme data
- 12.3Program maintenance — perfective, adaptive and corrective maintenance; analysing and amending an existing program
Video lectures13ZAK's YouTube channel · play here
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Infographics3draw these the way the examiner expects · download as PNG
Choosing test data
Waterfall, iterative & RAD
Testing & maintenance
Key terms13use these exact words in the exam
Dotted terms are defined in the glossary.
Code help2referenced to the Cambridge pseudocode guide
Test data table for a validation routine
textRule: mark must be an integer 0–100 Type Test value Expected Normal 56 accepted Extreme 0 / 100 accepted Boundary -1 / 101 rejected Abnormal "abc" / 3.5 rejected
FUNCTION LookupPrice(Code : STRING) RETURNS REAL// STUB — real database lookup not written yetRETURN 9.99ENDFUNCTIONDECLARE Total : REALTotal ← LookupPrice("A1") * 3OUTPUT "Total (using stub) = ", Total
Playground examples5runnable programs for this topic
- Run
Stepwise refinement — a bank menu built from modules
The main program only shows the menu and CALLs procedures; each module does one job (a structure chart in code).
ASPseudocodeProcedures & functions §8.1 · 9618 §9.1 - Run
Trace table practice
A typical dry-run question. Run it, then open the Trace table tab and check it against your own table.
O LevelASPseudocodeValidation, testing & exceptions 2210 §7.4 / 9618 §12.3 - Run
Normal, boundary and abnormal test data
Drive a function with each kind of test data and check the results against what you expected.
ASPseudocodeValidation, testing & exceptions 9618 §12.3 - Run
Validation loop — range and type checks
Keep asking until the input is a whole number between 1 and 100. try/except catches the ValueError from int().
O LevelASPythonValidation, testing & exceptions §7.3 ↔ Python, A2 §20.3 - Run
ISBN-13 check digit
Weights 1 and 3 alternate; the check digit makes the total a multiple of 10.
O LevelASPythonValidation, testing & exceptions 2210 §2 / 9618 §6
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