During an interview, a technician may well say that he “troubleshoots” and “works safely”. It is only when you present him with a realistic scenario that you can see whether he carries out the correct checks, sets priorities and remains calm under pressure. Good Case study questions for a mechanic’s job application help you to highlight that work behaviour, without having to organise a whole day of assessments.
What do you want to measure with a case study for technicians?
A case study is neither a knowledge test nor a puzzle. It is a mini-simulation of real-world practice, in which you assess someone’s approach: what information do they seek, what risks do they identify, and how do they reach a decision?.
Choose 3–5 areas of behaviour and skills in advance that really make a difference in your work. Otherwise, the case study will turn into a disorganised discussion and you’ll end up assessing candidates based on gut feeling after all.
- Fault analysis: formulating hypotheses, ruling them out, measuring, and providing feedback.
- Safety awareness: recognising risks, stopping when in doubt, adopting a lockout/tagout mindset.
- A quality-focused approach: thorough diagnosis, documentation, final check.
- Working together: handover, liaising with production/planning, asking for help.
- Customer focus or service orientation (for field staff): managing expectations, explaining things clearly.
If you already use a structured approach to interviews, this will fit in well with a set format. See also How to conduct a structured interview in 8 steps for the basics and the scoring system.
How to design case study questions for a mechanic’s job application, step by step
The approach outlined below is suitable for maintenance engineers, service engineers and breakdown engineers. You can also use it for electrical engineering, mechanical engineering or mechatronics, as long as you keep the context realistic.
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1) Start with your actual faults and jobs
Select three recent real-life cases: a recurring fault, an urgent job and a preventative task that often goes wrong. Choose one that is representative of 70% in the workplace.
Make sure you don’t create a case study that relies solely on your specific machinery “off the top of your head”. You want to base your reasoning on measurements, not just brand knowledge.
2) Write the case study in a single paragraph, including just enough details
A good case study should fit on half a sheet of A4. Provide relevant details, but leave room for questions from the candidate.
- What is the issue, and how long has it been going on?
- What has already been tried (by the operator/colleague)?
- What restrictions are there (time, production continues, safety)?
Avoid underhand tactics. If you have to “trap” the candidate, all you’ll be measuring is stress and mistrust.
3) Structure the questions: first the thought process, then the choices
Start with an open-ended question that sets the stage for the step-by-step plan. Then move on to asking follow-up questions about risk, diagnosis and communication.
- “What’s your first step, and why?”
- “What information are you still missing?”
- “What are you going to measure or check?”
- “When do you stop and move up a gear?”
Let the candidate think out loud. That gives you much more observable behaviour than just the final answer.
4) Add a realistic twist (but only one)
In real life, something always comes up. Add one twist to help you prioritise and assess safety.
- The fault reoccurs after 30 minutes of operation.
- There are doubts as to whether it is safe to open the machine.
- A planner asks us to carry on “just for a moment”.
Don’t judge whether someone mentions your internal procedure exactly as it is, but whether they are applying the right principles.
5) Create a scorecard with anchors for 1–3–5
Even without a rubric, the case study is still about making an impression. Define in advance what “weak”, “adequate” and “strong” mean for each criterion.
A simple scorecard fits in well with your wider selection. If you don’t have one yet, take a look at Create a selection scorecard for hiring managers for a practical format.
| Criterion | 1 (weak evidence) | 3 (satisfactory) | 5 (strong evidence) |
|---|---|---|---|
| Fault analysis | Speculates on the cause, skips measurements | Works logically, checks assumptions | Hypothesis-driven, measures and verifies |
| Safety | Downplays risks, looks for shortcuts | Follows rules when they are clear | Identifies risks independently and proposes control measures |
| Communication/transfer | Unclear, no feedback | Shows status and next step | Align expectations, document for future reference |
6) Choose the right format: oral, in writing or at the workplace
The format determines what you can observe. Choose the one that suits the role and your risks.
- Oral case study: quick, good for critical thinking and communication.
- Paper/whiteboard: ask someone to draw up a step-by-step plan or a measurement plan.
- Workplace simulation: only if you can demonstrate it safely (without affecting production).
For roles that have an impact on safety, it is wise to explicitly assess candidates’ understanding of safety standards. In the Netherlands, the employer is responsible for ensuring safe working conditions; the basis for this is Arboportaal on the Working Conditions Act.
7) Keep it fair and legally defensible
Use the same case study (or two variations using the same marking scheme) for all candidates. Otherwise, you’ll be comparing apples with oranges.
You should also set out what information you record and how long you retain it. Job application data is subject to data protection regulations; the Dutch Data Protection Authority provides practical guidance on Job application details and privacy.
8) After 3 months, assess whether your case study is predictive
After 8–12 weeks, ask your line manager for feedback: does the employee’s behaviour at work match what you observed in the case study? Pay particular attention to recurring signs of a mismatch (e.g. safety or the quality of diagnosis).
Only then should you tweak your case study. Making small adjustments will refine it much more quickly than endlessly tinkering with it before the first round.
Examples of effective case study questions for technicians
Below are three formats that work well in many technical environments. You can adapt them to suit your installation, vehicles or systems.
Case Study 1: Recurring fault (troubleshooting)
- “A conveyor belt stops three times per shift with the same error message. What is your approach once the error is reported?”
- “Which measurements do you take first, and what do you expect to see?”
- “What do you document to ensure the next mechanic doesn’t have to start from scratch?”
Case Study 2: Safety under pressure (awareness of standards)
- “You hear an unusual noise coming from a moving part, but production needs to carry on. What do you do, and what do you say?”
- “What risks do you want to rule out before opening anything?”
Case Study 3: Preventive maintenance with scope creep (prioritisation)
- “You’re scheduled for PM, but you receive two minor notifications in the meantime. How do you organise your schedule?”
- “When should you escalate or pass it on, and how do you explain that?”
Common mistakes in practical case studies for mechanics
- Too theoretical: asking about patterns off the top of your head, without any context. You’re missing the practical application.
- Too long: a 30-minute case study without a rubric becomes a second interview.
- No score: “gut feeling” still wins out over evidence.
- No calibration: interviewers use the same scale differently, and the same issues keep cropping up.
Much of this sort of noise is also reflected in general selection. The short checklist in These 4 mistakes are costing you your best candidates helps you to recognise those pitfalls throughout your entire process.
A next step that takes very little time
If you choose one technician role and create a single case study and scorecard for it, you’ll be able to carry out more consistent assessments within a week. Would you like to discuss which case study is most predictive for your maintenance or service team, and how you can integrate it into a data-driven selection process? In that case, a brief consultation is often all it takes to quickly fine-tune things.