Two people can write the same word in the same section of a profile and mean two unrelated things. "RAG" can describe the ability to explain the principle in a meeting, or ownership of a production system whose retrieval quality is measured every week. The word carries no depth, and that is why most skill lists are unreadable.
This guide is not another list of technologies to learn. It offers a scale for thinking about the depth of any AI skill, and for answering a question few people settle for themselves: at what point can I say I actually have this skill?
A five-level progression scale
What follows is not an official framework or a recognised standard: it is a teaching scale, useful because it separates things everyday vocabulary merges. It applies to any AI skill, technical or not.
- 1
Level 1 — Understand
explainBeing able to say what the technology does, what it does not do, its main use cases and its important limits. Enough to follow a conversation without misidentifying the problem.
- 2
Level 2 — Use
applyBeing able to use it correctly in a defined context, obtain a usable result, and recognise the situations where the output is not trustworthy.
- 3
Level 3 — Build
produceBeing able to produce something reproducible and justify your choices: why this approach, why not the other, and under what conditions it holds.
- 4
Level 4 — Evaluate and diagnose
measureBeing able to say why a system works or fails, measure its quality with a defensible protocol, and locate the cause of a regression.
- 5
Level 5 — Design, decide, operate
ownWhere the role requires it: arbitrating between quality, cost, latency, security and integration, keeping the system running, setting governance rules and owning the limits you chose.
No job needs level 5 on every skill. A role is defined as much by the skills it requires in depth as by the ones where level 1 or 2 is plenty.
The same skill at five different depths
The scale becomes useful when applied to words that genuinely appear in profiles and job ads.
Prompting
Understand: knowing why phrasing changes the output and why reproducibility is not guaranteed. Use: reliably getting a usable result on a repeated task. Build: producing versioned instructions, tested on representative cases. Evaluate: measuring regressions when a model or an instruction changes. Design: embedding those instructions in a system whose cost, latency and refusal cases you control.
RAG
This is the most revealing example, because all five levels hide behind one acronym: explaining the principle; assembling a demo that answers correctly on a few documents; designing chunking and retrieval for a real corpus; diagnosing whether a failure comes from retrieval or from generation; operating the system, with data freshness, access rights and cost under control.
Agents
Understand: telling a chain of calls apart from real autonomy. Use: getting a tool-using agent to work on a scoped task. Build: defining tools, permissions and stopping conditions. Evaluate: measuring failure rates and behaviour when a tool errors. Operate: handling idempotency, retries and side effects on real systems.
Evaluation
Understand: knowing that an occasional human judgement is not a measurement. Use: applying an existing protocol. Build: assembling a representative set of cases, including hard ones. Diagnose: interpreting a gap and tracing it back to a cause. Decide: setting the bar above which a feature can be put in users' hands.
AI literacy and copilots, for a non-technical role
Understand: knowing what an assistant can produce and what it fabricates. Use: fitting it into your work without delegating verification to it. Build: documenting a way of working that a team can reuse. Evaluate: observing where the tool saves time and where it costs time. Decide: setting usage rules around sensitive data. Level 5 exists here too — it simply is not about code.
What a skill list says
"LLM, RAG, agents, evaluation." Four words that could match four articles read, or four systems held in production.
What a named depth says
"RAG: retrieval design and quality diagnosis on an internal corpus. Agents: usage level, on scoped tasks." The reading is immediate, and the modesty on one point makes the other credible.
Naming a low level on a skill does not weaken a profile. It makes the higher claims believable.
Build a progression plan instead of accumulating
The scale is mostly a way of deciding what to do next. The reasoning fits in six questions, in this order, and it is redone whenever the objective changes.
- 1
Target role
1Which responsibility am I actually aiming at? Without a destination, every kind of progress looks equally justified.
- 2
Required skills
2Which ones does that role genuinely need? The list is shorter than expected, and often contains non-technical skills.
- 3
Expected depth
3For each, which level is enough? The most frequently skipped step, and the one that avoids the most wasted effort.
- 4
Current level
4Where you honestly stand, judged by what you could demonstrate under questioning.
- 5
Missing evidence
5What is missing for that level to be visible from the outside?
- 6
Next step
6One single action, chosen to close the most blocking gap — not the most interesting one.
"Learn more" is rarely the right next step
The usual reflex when facing a gap is to consume more content. Sometimes that is right, especially at level 1. Beyond it, the gap is almost never a knowledge deficit: it is a deficit of practice, measurement or evidence, and reading more does not close it.
- Practise, when you understand the theory but have never produced a result yourself.
- Measure, when you produce results without being able to say whether they are good.
- Diagnose, when you know a result is poor but not why.
- Document, when you can do the work but nobody can observe it.
- Explain, when the skill exists but stays uncommunicable in an interview.
- Ship to production, when the target role requires operational responsibility.
- Work with another function, when the gap is about context rather than technique.
Training and certifications: what they prove, and what they do not
A certification is neither a false signal nor sufficient evidence. It attests to a structured path, which has real value, particularly for organising learning or crossing level 1. The misunderstanding starts when it is presented as equivalent to professional practice.
- Having taken a course: time invested in a given programme.
- Knowing a concept: being able to explain it and name its limits.
- Being able to use it: getting a usable result in a defined context.
- Having professional evidence: having held an observable responsibility, with decisions you can defend.
All four statements can be true at once. Presenting them in order, without merging them, is what separates a precise profile from an overstated one.
Place a skill before displaying it
Run this over each skill highlighted in a profile or an application.
- I can name the level I have actually reached on this skill.
- I know which level the role I am targeting requires on that same skill.
- I can explain what the technology does not do, not only what it does.
- I have obtained a result on my own, outside a guided tutorial.
- I could say why a result is poor, not just that it is.
- There is an observable trace of this skill: project, decision, documentation, responsibility.
- I do not present a completed course as professional practice.
Key points
- A word in a skills section carries no depth: the level is what informs.
- Five levels are enough: understand, use, build, evaluate, design and operate.
- No role requires the top level on every skill.
- A progression plan starts from the target role, not from the catalogue of available technologies.
- Past level one, the gap is usually a lack of practice, measurement or evidence.
- Taking a course, knowing, being able to use, and holding professional evidence are four distinct things.
- Progression
- Skill levels
- Learning