VCE Applied Computing: Data Analytics (Year 12) · Unit 3 — Data Analytics: Analysis and Design · 16m read

The Problem-Solving Methodology

Every Units 3–4 Applied Computing SAT, SAC and exam question is framed by the problem-solving methodology. Know its stages and key terms precisely and you will understand what every question is really asking — whichever study you take.

Learning objective: Apply the four stages of the VCAA problem-solving methodology (PSM) to both Data Analytics and Software Development.

By the end of this lesson you can:

• I can name and describe the four stages and their activities.
• I can place a task in the correct stage.
• I can explain the difference between efficiency and effectiveness.

The PSM is a road map. Analyse, design, develop, evaluate — follow the route and you won't get lost building a solution.

Four stages

ANALYSIS:
• Solution requirements — FUNCTIONAL (what it must do) and NON-FUNCTIONAL (qualities such as usability, reliability).
• Solution constraints — economic, technical, social, legal, usability.
• Scope — what the solution will and will not do.

DESIGN:
• Generating design ideas and selecting one using criteria.
• Solution design tools: data dictionaries, object descriptions, pseudocode, mock-ups, data flow and use case diagrams.
• Evaluation criteria are written here, to be used later.

DEVELOPMENT:
• Manipulation (coding or building), validation, testing and documentation.

EVALUATION:
• Strategy — when and how the solution will be evaluated.
• Report — judging the solution against the evaluation criteria.

EFFICIENCY vs EFFECTIVENESS:
• EFFICIENCY — time, cost and effort to produce or use the solution.
• EFFECTIVENESS — how well it meets its goals: accuracy, completeness, usability, reliability, timeliness, attractiveness.

Quick reference

| Stage | Activities |
|---|---|
| Analysis | Requirements, constraints, scope |
| Design | Pseudocode, mock-ups, data dictionaries |
| Development | Code, validate, test, document |
| Evaluation | Against criteria |
| Project management | Gantt chart |

Key ideas at a glance

• Functional vs non-functional requirements: What vs how well.
• Constraints: Economic, technical, social, legal, usability.
• Design tools: Pseudocode, IPO charts.
• Evaluation criteria: From analysis.

Worked example (Medium)

In which stage does each task belong? (a) writing pseudocode (b) checking that the app meets the evaluation criteria (c) identifying that the app must work offline (d) entering test data.

1. (a). Design.
2. (b). Evaluation.
3. (c). Analysis — it is a requirement (non-functional) or constraint.
4. (d). Development (testing).

Answer: (a) design (b) evaluation (c) analysis (d) development

Common mistakes

• Confusing testing with evaluation Testing checks the solution works; evaluation judges how well it meets its goals after use. Fix: Testing is in development; evaluation comes after implementation.
• Mixing up efficiency and effectiveness They are distinct VCAA terms. Fix: Efficiency = resources; effectiveness = quality of outcome.

Why methodology matters

Large software projects often fail because requirements were misunderstood or changed without planning.

A clear methodology like the PSM reduces risk by catching problems early, when they're cheap to fix.

Practice questions

1. "The system must respond within two seconds" is best described as:

   1. A functional requirement
   2. A non-functional requirement
   3. A constraint
   4. An evaluation strategy

   (1 marks)

Summary

• Analysis, design, development, evaluation.
• Requirements: functional vs non-functional.
• Efficiency (resources) vs effectiveness (quality).