Chapter 4 · 4 hours
Problem Solving and Decision Making
Practice questions
Practice questions and answers
2 exam-style questions on this chapter, written for this site from the official syllabus. We haven’t found past IOE papers for this subject yet; if you have some, share them in the community.
- Practice · 6 marks
Explain the problem solving process and the stages of creative problem solving. Describe brainstorming, giving its rules and the way a session is conducted.
Answer
Problem solving process
Problem solving is a systematic way of moving from a given situation to a desired one. The usual steps are:
- Identify and define the problem (what is wrong, what is wanted).
- Collect facts and analyse the causes.
- Generate possible solutions.
- Evaluate the solutions against criteria and constraints.
- Select and implement the best solution.
- Review the result and feed back any lessons.
Creative problem solving
Creative problem solving is used when the usual methods fail and a new idea is needed. The stages are:
| Stage | What happens |
|---|---|
| Preparation | Study the problem and gather information |
| Incubation | The problem is left aside while the mind works on it unconsciously |
| Illumination | A new idea suddenly appears (the "aha" moment) |
| Verification | The idea is tested, refined and developed |
Techniques that help are brainstorming, analogy, inversion (asking how to make the problem worse), checklists, morphological charts and questioning assumptions. Creativity is helped by a relaxed atmosphere and delay of judgement. Invention is the result when the idea is new, useful and can be made to work.
Brainstorming
Brainstorming is a group method to produce many ideas quickly.
Rules:
- No criticism or evaluation during idea generation.
- Welcome unusual and wild ideas.
- Aim for quantity; more ideas give more good ideas.
- Combine and improve the ideas of others ("hitch-hiking").
Conduct of a session: a group of 5 to 12 people with a leader and a recorder; the problem is stated clearly; the session lasts 20 to 40 minutes; all ideas are written visibly. Afterwards the ideas are grouped, evaluated and the best are developed further.
- Practice · 5 marks
Differentiate between needs, goals, constraints and compromises in a design problem. Explain how a good problem statement is written and the criteria for evaluation are set, using the design of a hand-operated water pump for a village household as the example.
Answer
Differentiation
| Term | Meaning | Example (hand pump) |
|---|---|---|
| Need | What the user requires; the reason for the design | Safe drinking water from a well for a household |
| Goal | A desirable target that should be achieved as far as possible; it may be measured | Low cost, light weight, easy to repair locally |
| Constraint | A limit that must not be violated; a pass/fail requirement | Lift of 10 m, flow at least 10 litre/min, cost below Rs 5000, made from locally available materials |
| Compromise | A trade-off between conflicting goals or constraints | Thicker pipe gives long life but increases cost, so a medium thickness is chosen |
Conditions are the working circumstances (outdoor use, dusty and wet, operated by a child or an adult). Criteria for evaluation are the measures used to compare alternatives, taken from the goals and constraints.
Writing the problem statement
A good problem statement is short, specific, solution-neutral, and measurable. It says what is to be achieved, not how. It includes the user, the function, the main constraints and the performance targets.
Example: "Design a hand-operated pump to raise at least 10 litre/min of water from a depth of 10 m for a family of six. Operation force should not exceed 150 N, the cost should be below Rs 5000, and it should be maintained with common tools."
Criteria for evaluation for the pump
- Discharge and ease of operation (force, stroke).
- Initial cost and cost of maintenance.
- Reliability and life.
- Use of local materials and skills.
- Safety and hygiene (no contamination of water).
Each criterion is given a weight and each concept is scored (decision matrix) so that the best design is selected objectively.
Written from the official syllabus. Questions and answers are written for this site; check them against your class notes.
Chapter titles and hours from the IOE syllabus ↗