In the infrastructure and DevOps world, I have interviewed hundreds of engineers over the years. Many of them looked excellent on paper : Strong CVs, recognized companies, impressive certifications, and clear answers during interviews. Yet sometimes, a few days after joining the team, the reality becomes visible.
The first real incident happens. A deployment pipeline fails. A Linux service stops responding. A production issue needs investigation. And suddenly the confidence seen during the interview disappears. This situation is not rare. In fact, it happens much more often than most companies are willing to admit.
And the reason is simple: traditional interviews measure knowledge, not operational capability.
Table of Contents
1. Interviews reward preparation, not necessarily execution
5. The impact on the consultant, the team, and the company’s reputation
7. Observing engineers in real situations
Most technical interviews follow a familiar structure. Questions about:
A candidate who prepares well can answer these questions convincingly.
Many engineers today prepare for interviews exactly like students prepare for exams. They learn the patterns. They anticipate the questions. They rehearse explanations. But real technical work rarely looks like an interview.
In production environments you face:
What matters then is not memorized knowledge, but how someone thinks and acts under uncertainty. That difference is what interviews often fail to capture.
Another factor is something few people talk about: interviewer fatigue. Hiring managers often run several interviews in one day.
By the third or fourth interview:
A candidate who appears confident can easily pass. Not because the process is bad, but because humans are human.
Another reality in infrastructure roles is that every environment is different. A DevOps engineer may have worked with Kubernetes before. But your environment might combine:
What matters is not whether the candidate knows Kubernetes theory. What matters is whether they can navigate complexity and learn quickly inside your environment. Interviews alone rarely test that.
The moment of truth arrives during the first real task: Investigating logs, tracing a deployment issue, or understanding how different systems interact. That is when teams discover the real operational level of a consultant. Sometimes the candidate performs brilliantly, but sometimes the gap becomes visible. And that gap has consequences for everyone involved.
When an engineer realizes they are struggling more than expected, the situation can become very uncomfortable. Many consultants hesitate to ask questions because they fear appearing weak. They try to catch up quietly. This creates stress and isolation. Instead of learning quickly with the team, they start protecting themselves.
The team also feels the impact. Colleagues suddenly need to:
And an uncomfortable thought appears: “Why did our hiring process approve this profile?”
In consulting environments, reputation spreads quickly. Engineers remember their experiences. If they repeatedly encounter underqualified consultants from the same firm, a perception forms.
In France, many experienced engineers already carry skepticism toward consulting companies. Not because consulting itself is bad, but because technical quality has not always been consistent across the industry. One weak placement can reinforce that perception.
The issue is not that recruiters or managers are doing a poor job. The issue is that the validation method is incomplete. A CV tells a story, and an interview tests knowledge, but neither fully reveals how someone behaves when facing real technical situations.
Over the years, while restructuring teams as a transition manager, I started doing something different. Instead of relying only on interviews, I simulated realistic scenarios.
I wanted to see:
The difference in insight was immediate. That experience eventually led to the creation of Scalyz. However, even without any platform, the core lesson remains simple:
if you want to understand an engineer’s real capability, you must observe them in action, not only in conversation.
Technical interviews are useful, but they only tell part of the story. To truly assess an engineer’s level, you need to see how they think and act when faced with a real problem.
Book a demo now to discover how Scalyz can support you.
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