An engineering team designing a hospital medication dispenser skips user interviews and instead builds what they believe nurses need based on technical specifications. The device is then rejected by nursing staff as unusable. What core mistake did the team make?

They used the wrong materials for the housing They skipped regulatory approval They optimised for what engineers could quantify rather than what users actually care about They failed to patent the design before showing it to nurses

A design team creates a persona: 'Amara, 68, retired teacher with mild arthritis and moderate smartphone experience.' During design reviews, team members debate every decision by asking 'Would Amara find this easy?' What is the primary engineering value of using a persona this way?

It ensures the product is only usable by people exactly like Amara It replaces the need for usability testing It focuses the team on a realistic representative user rather than abstract or idealized users It guarantees regulatory approval for the product

A user journey map for a blood glucose monitor reveals that patients feel anxious while waiting for results, often misread the display under poor lighting, and struggle to find their data when talking to their doctor. Which part of the design process does this tool most directly support?

Selecting the most cost-effective manufacturing process Identifying pain points and opportunities beyond the moment of product use Determining the optimal battery chemistry for the device Writing the device's software requirements specification

City engineers add a sloped ramp at every street corner (a curb cut) to comply with wheelchair access laws. Over time they observe the ramps are also used heavily by people with prams, delivery workers with trolleys, and cyclists. This outcome best illustrates which design principle?

Universal design benefits a much wider population than the originally targeted users Compliance with legal accessibility standards is sufficient for good design Engineers should always prioritise pedestrian safety over cyclist convenience Ramps are more expensive to build than steps but worth the cost

According to Don Norman's error taxonomy, a surgeon intends to cut the correct artery but makes an involuntary hand movement and nicks an adjacent vessel. This type of error is classified as a:

Mistake — the surgeon chose the wrong surgical approach Slip — the intention was correct but the action went wrong Forcing function — the environment constrained the surgeon's movement Affordance failure — the scalpel did not suggest the correct grip

A car ignition system requires the driver to press the brake pedal before the engine will start. This is an example of which error-prevention design technique?

Affordance — the pedal communicates that it should be pressed Feedback — the driver is told the engine failed to start Forcing function — a constraint that prevents an undesired action Mapping — the pedal layout mirrors the driver's mental model

An HCD team is developing a children's asthma inhaler. They have sketched paper mockups and are now creating foam-core models that users can hold and manipulate. Which stage of the prototyping process are they in, and what is its main purpose?

Low-fidelity prototyping — to quickly communicate an initial concept High-fidelity prototyping — to demonstrate the finished product to regulators Medium-fidelity prototyping — to test form, grip, and basic interaction before committing to costly manufacturing Post-market surveillance — to collect real-world usage data

A usability study recruits five participants to test a new electronic prescription system. Research evidence suggests this sample size will uncover approximately what fraction of the product's usability problems?

About 25% of usability problems About 50% of usability problems About 85% of usability problems 100% of usability problems — five is the minimum reliable sample

During a usability test of a new glucose monitoring app, a researcher asks participants to say aloud what they are thinking as they navigate the interface, without guiding them. This technique is called:

Cognitive walkthrough Heuristic evaluation Think-aloud protocol A/B testing

A company designs a touchscreen interface for elderly patients in a hospital ward and adds voice control as an accessibility feature. Years later, the voice control is adopted widely by busy nurses who cannot touch a screen with gloved hands. This reflects which broader pattern in assistive technology development?

Accessibility features always increase product cost without wider benefit Features designed for disability often benefit a far wider population Hospitals are the primary market for accessibility research Voice control was invented specifically for gloved healthcare workers

A medical device company launches an insulin pump and collects structured reports from hospitals when the device causes an adverse event, then uses that data to redesign the alert system. This activity is best described as:

Usability testing — assessing how easily users operate the pump A/B testing — comparing two alert system designs simultaneously Post-market surveillance — monitoring real-world performance to drive design improvements and meet regulatory obligations Regulatory submission — seeking approval for a new device classification

A team designing a wheelchair-accessible ATM discovers that in Japan, users expect the screen to be at a different height than in the USA, and that the colour red — used for the cancel button in the USA — is associated with good luck rather than danger in some East Asian cultures. What does this challenge illustrate about human-centered design?

ATM design is fully standardised internationally and requires no localisation Cultural context means that design assumptions valid in one setting can fail or cause confusion in another The solution is simply to remove all colour from the interface Cultural differences only affect marketing, not engineering design