Product Development and R&D Engineer Interview Questions for Medical Devices (With Answers)

Product development and R&D engineers in medical devices are judged on more than engineering skill. Interviewers want to see that you can work within design controls, think about use errors, choose materials responsibly and plan for labelling and market access. This guide has 8 model questions with answers and three case studies with ideal answers covering usability, material changes and UDI.

What to prepare

Choose one project you can walk through from user needs to design transfer, including what changed along the way. Be ready to discuss design controls, ISO 14971 risk management, usability engineering, biocompatibility and UDI.

Eight common questions with model answers

1. Walk me through the design control process.

Model answer: “Plan the project, capture user needs, turn them into design inputs, create design outputs, verify the outputs against the inputs, validate the device against user needs in the intended use conditions, review at stages, transfer to manufacturing and keep a design file. Risk management runs throughout, and changes are controlled and recorded.”

2. What makes a good design input?

Model answer: “It is specific, measurable and testable, traceable to a user need or a risk control, and complete enough for verification. ‘The device should be easy to hold’ is weak. ‘The handle diameter is between 28 and 34 mm and the device can be operated one-handed by 95% of the target users’ can be verified.”

3. What is the difference between verification and validation?

Model answer: “Verification asks whether we built the device right: do outputs meet inputs. Validation asks whether we built the right device: does it meet user needs and intended use, with representative users in realistic conditions. Verification can use bench tests. Validation needs real or simulated use.”

4. How do you handle a requirement change late in development?

Model answer: “Through formal change control. I assess the impact on risk, other requirements, verification, validation, labelling and regulatory status, plan the retesting needed, and get the right approvals. If the change is large, I discuss the schedule effect openly. A late change is not unusual; an uncontrolled one is the problem.”

5. What is design transfer and what documents result?

Model answer: “It is making sure the design is correctly translated into production: specifications, drawings, work instructions, inspection methods and validated processes. Records historically called the design history file, device master record and device history record are now described under ISO 13485 as the design and development file and the medical device file, with batch or unit records for production. The key is that production can reproduce the design reliably.”

6. How do you apply usability engineering?

Model answer: “Define users and use environment, analyse use-related risks, write user interface requirements, test early with real users, iterate, then run a summative evaluation with representative users on the final design. Any use error leads to root cause analysis and a design fix first, with labelling as a last resort.”

7. How do you choose materials and show they are safe?

Model answer: “I consider function, manufacturability, sterilisation compatibility and biological safety. I use the contact category and duration to plan a biological evaluation, with supplier data and chemical characterisation, and add testing for gaps. I lock the material specification and supplier through change control, since a changed grade can alter the safety conclusion.”

8. Tell me about a design problem you found late.

Model answer (STAR): “In design verification, a snap-fit housing cracked after accelerated ageing (situation). I owned the investigation (task). I analysed fracture surfaces, found a stress concentration at a corner and a moisture-sensitive resin, changed the radius and material grade, and repeated the ageing tests under an updated protocol (action). The new design passed with margin and the lesson was added to our design review checklist (result).”

Case study 1: nurses keep misconnecting a line

Scenario: Formative testing of an infusion accessory shows that two of eight nurses connect a line to the wrong port. Marketing suggests adding a warning to the instructions.

Ideal answer: “A warning is the weakest control. I would first find out why the error occurs, such as similar connectors, poor labelling or low light. Then I would look for an inherently safe design fix, for example different connector geometries that prevent misconnection, or colour and shape coding as a second layer. Where residual risk remains, I would add information for safety. I would update the use-related risk analysis, retest formatively and include the scenario in the summative evaluation. I would explain to marketing that regulators and auditors expect risk reduction by design first.”

Case study 2: supplier changes a resin during the build

Scenario: During pilot builds you discover that a supplier switched the grade of a polymer used in a skin-contacting housing without telling you.

Ideal answer: “I would quarantine affected material and notify quality. Then I would assess the change: material composition, processing, mechanical properties, sterilisation compatibility and biological safety. Because the housing contacts skin, I would assess whether existing biocompatibility data still apply and what chemical or biological tests are needed. Any parts built with the new grade should not be used for verification or validation evidence until the impact is understood. I would raise a nonconformance with the supplier and tighten change notification in the agreement. See also our supplier controls guide.”

Case study 3: a new pack size for another market

Scenario: Sales wants to launch a box of 50 for a new market, where the current product is sold as a box of 20. The device itself does not change.

Ideal answer: “A different packaging configuration usually needs its own UDI-DI, because the DI identifies the packaging level and quantity. I would check the DI assignment rules, update labels with new data, barcodes and any language or market requirements, and register the new DI in the relevant databases, such as GUDID and EUDAMED, before the product is placed on the market. I would also assess whether the packaging change affects sterilisation, shelf life or shipping validation, and process it through change control. Label verification must confirm that human-readable and machine-readable data match.”

Mistakes to avoid

• Describing design controls as a documentation exercise done after the engineering.
• Offering labels and warnings as the first solution to a use error.
• Treating biocompatibility as a one-time test.
• Not mentioning risk management in your project story.

Frequently asked questions

Do I need regulatory knowledge as an engineer?

Yes. Basic understanding of ISO 13485, design controls, ISO 14971 and the main US and EU requirements is expected. See US FDA regulations and EU MDR and IVDR.

What should I bring to the interview?

A concise project summary or portfolio, with confidential details removed. Be able to show the V-model of requirements, tests and traceability.

What else should I read?

Our design controls and risk interview guide and validation engineer guide cover related questions.

Model answers are examples; adapt them to your real experience.

Talk to the AptSkill team

Preparing for a product development interview? Send us a message.