How ergonomics improves a product
Ergonomics is the study of how people interact with the products, systems and environments they use.
It asks one question of every design decision: does this fit the human being who will use it?
A product that ignores the body, the senses or the mind of its user may still work on the bench, but it fails in someone's hands.
The IB asks you to describe how ergonomics makes a design better in five distinct ways.
Treat them as five separate claims, because a mark scheme credits each one on its own.
The five gains
- Safer. Hazards are designed out, not left to the user's care. A kettle whose handle sits away from the spout keeps the hand clear of steam; rounded corners on a child's toy remove a cutting edge.
- More usable. The product is easy to learn and hard to use wrongly. Controls are where the hand expects them, and their meaning is obvious without a manual.
- More functional. The product does its intended job in real conditions. A torch that can be gripped with a wet or gloved hand still works when it is needed most.
- More efficient. The task takes less time, effort or energy. A well-placed handle on a heavy case reduces the muscular effort of carrying it.
- More effective. The user actually achieves the goal. A medicine bottle that an arthritic patient can open delivers the treatment; one they cannot open is ineffective, however strong its seal.
A tin opener that opens the tin only after two minutes of struggle is effective but not efficient.
Three kinds of human factor
Ergonomics draws on three bodies of knowledge, which the rest of this subtopic covers.
Anthropometrics measures body size.
Physiology deals with the body's capabilities and limits, such as strength, fatigue and hearing.
Psychology deals with how the senses and the mind take in and interpret information.
Good ergonomic design uses all three together.
- Ergonomics: the relationship and interaction between people and the products, systems and environments they use, applied to make designs fit their users.
- Usability: how easily and successfully a user can learn and operate a product to achieve a goal.
- Efficiency: achieving a task with the least time, effort or energy.
- Effectiveness: the degree to which a product lets the user achieve the intended outcome.
The OXO Good Grips vegetable peeler went on sale in 1990.
Sam Farber developed it with the consultancy Smart Design after noticing that his wife, Betsey, found ordinary peelers painful to hold because of arthritis in her hands.
Describe how its ergonomics improve the product.
1. Identify the ergonomic features: a large, oval handle in a soft, non-slip synthetic rubber, with flexible fins where the thumb and finger rest.
2. Link each feature to a gain. The large diameter spreads grip force over more of the palm, so less force is needed: the peeler is more efficient and more usable for weak or painful hands.
3. The non-slip surface keeps grip when the hand is wet, so the blade is less likely to slip towards the user: it is safer.
4. Because users of many abilities can now peel without pain, the product is effective for a much larger population, not only for people with arthritis.
Answer: a full description names each feature and ties it to a specific gain (safety, usability, efficiency or effectiveness), with the reason, instead of listing features alone.
When a question says Describe how ergonomics improves a product, give feature, then gain, then reason, for each point.
"It has a soft grip" earns little on its own; "the soft, wide grip spreads the force over the palm, so users with weak hands need less effort" earns the mark.
- Writing "it is more comfortable" for every point. Comfort is not one of the five gains; say which gain the comfort produces and why.
- Treating efficient and effective as the same word. Effective means the goal is reached; efficient means it is reached with little waste of time, effort or energy.
Check your understanding
1. State the three kinds of human factor data that ergonomics draws on. [1]
2. Distinguish between efficiency and effectiveness, using a door handle as the example. [2]
3. Describe two ways ergonomic design could make a cordless drill safer to use. [2]