How to assess · For hiring teams
How to Assess Power BI Skills When Hiring
The test formats that actually work for Power BI, what a strong answer looks like, sample questions and a scoring rubric you can use as-is.
The short answer
Assess Power BI with a task, not a conversation: model and measure from raw tables, fix a broken report, ai-scored assessment (e.g. cohesyve) or report critique. Score it against written criteria you fix before you see any submissions, and weight the criteria that the role actually depends on.
- Builds a star schema with a proper date table before writing a single measure
- Writes DAX measures that return correct results under any filter context, and can explain why
- Chooses measures over calculated columns and can say when the reverse is right
- Keeps models fast: right data types, no unnecessary columns, aggregation where needed
Paste a job description; Cohesyve generates a role-specific assessment and rubric. Ten candidates free, no card.
Power BI skill is easy to claim and easy to fake in an interview, because the tool makes it simple to produce a dashboard that looks finished. What it does not make simple is a data model that stays fast as data grows, DAX measures that return the right number under every filter, and a report that a stakeholder can actually use to make a decision. Those are the skills that separate an analyst from a report builder. This page covers how to assess Power BI as it is used in practice: modelling, DAX, performance, and the judgement to design for the person reading the report.
Why Power BI is worth testing
A weak Power BI hire produces dashboards that are slow, that show different numbers on different pages, and that nobody trusts within a quarter. The causes are always the same: a flat table instead of a star schema, calculated columns where measures belong, relationships that create ambiguity, and visuals chosen for looks rather than the question. Testing surfaces all of these in an hour, and it is the only way to tell a modeller from someone who has clicked through the interface.
What strong Power BI looks like
- Builds a star schema with a proper date table before writing a single measure
- Writes DAX measures that return correct results under any filter context, and can explain why
- Chooses measures over calculated columns and can say when the reverse is right
- Keeps models fast: right data types, no unnecessary columns, aggregation where needed
- Designs reports around a question and a decision, not around available charts
- Uses row-level security correctly and knows how it interacts with relationships
- Documents measures and can trace a number on a visual back to its source
Ways to assess Power BI
Model and measure from raw tables
Provide three or four flat exports — orders, products, customers, dates as a column — and ask for a model, four measures including a year-over-year comparison, and one page that answers a stated business question. Ninety minutes.
Pros
Cons
Best for Mid and senior analyst and BI developer roles.
Fix a broken report
Provide a report with a many-to-many ambiguity, a measure that double-counts, and a page that takes ten seconds to render. Ask the candidate to diagnose and fix each.
Pros
Cons
Best for Any level; scale via subtlety.
AI-scored assessment (e.g. Cohesyve)
Generate a Power BI task from the job description — a modelling design, a DAX problem, a report critique — with a rubric. Each candidate receives a different variant; reasoning is scored in writing.
Pros
Cons
Best for Screening a pool before hands-on rounds.
Report critique
Show a cluttered dashboard and ask what they would change and why.
Pros
Cons
Best for Roles heavy on stakeholder reporting.
Cohesyve
Run a Power BI assessment on your next opening
Cohesyve generates a unique Power BI task per candidate from your job description, with the scoring rubric attached. Questions are different for every applicant, so they cannot be shared or looked up.
What to test
Data modelling
Whether the model is a star schema that will scale.
DAX
Whether measures are correct under filter context.
Performance
Whether the report stays usable as data grows.
Report design
Whether the report helps a decision.
Sample Power BI questions
Why does a star schema matter in Power BI?
EntryLook for Simpler relationships, correct filter propagation, faster queries, simpler DAX.
When would you use a calculated column instead of a measure?
EntryLook for Row-level values needed for slicing or relationships; otherwise measures, which respond to filter context and do not bloat the model.
A total at the bottom of a table does not equal the sum of the rows. Why?
MidLook for Measures evaluate in each filter context; the total is not a sum of rows unless designed so; discusses iterators and context.
A report page takes twelve seconds to load. Where do you look?
MidLook for Performance Analyzer, expensive visuals and measures, model size and cardinality, relationships, DirectQuery versus import.
Design row-level security so regional managers see only their region, and explain the pitfalls.
SeniorLook for Roles with DAX filters on the dimension, propagation through relationships, testing with view-as, bidirectional relationships as a risk.
Red flags
- Loads everything into one flat table
- Uses calculated columns for everything
- Cannot explain filter context
- Has never used Performance Analyzer
- Chooses visuals for appearance rather than the question
Scoring rubric
| Criterion | Weight | What strong looks like |
|---|---|---|
| Modelling | 30% | Star schema with a date table; relationships are unambiguous. |
| DAX correctness | 30% | Measures are right under any filter; context is understood. |
| Performance | 15% | The model is lean and the report is fast. |
| Report judgement | 25% | Pages answer questions and support decisions. |
Mistakes hiring teams make
- Judging a portfolio of pretty dashboards without seeing the model
- Not testing DAX under filter context — the defining Power BI skill
- Skipping performance entirely
- Accepting a report that looks good but answers no question
- Assuming Excel skill transfers to modelling
Roles that need Power BI
Common questions
Can I assess Power BI without giving tool access?
Partly. Modelling design and DAX reasoning can be tested on paper, and a report critique needs only a screenshot. Confirm hands-on with finalists using a prepared dataset.
What is the single best Power BI question?
Ask why a total does not equal the sum of its rows. It tests filter-context understanding, which is the foundation of correct DAX.
How long should a Power BI assessment take?
Ninety minutes for a model-and-measure task; thirty for a critique or paper exercise.
Does Tableau experience transfer to Power BI?
Visualisation judgement transfers. The modelling and DAX layer is Power BI-specific and is where the difficult skill lives; test it directly.
Cohesyve · Skill assessments for hiring
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