Data Analyst
Structured interview questions for Data Analyst, with what a strong answer surfaces for each one.
BehavioralBusiness orientation Describe an analysis that changed a concrete business decision. What was the initial question, what did you find, and what was decided in the end?
What a strong answer surfacesThe ability to tell an analysis project along the chain of impact: question, method, result, decision. Bonus: the candidate names the stakeholders, the assumptions and the uncertainty of the data. Someone who only describes the method (I built a funnel) without naming the decision usually did reporting, not analysis. Someone who talks about strategic insights with no concrete number or action often compensates for a lack of business orientation with platitudes.
BehavioralData scrutiny and investigation Tell me about an analysis whose result you initially thought was wrong. What was the symptom, and how did you get to the truth?
What a strong answer surfacesA structured investigation method: check the data quality, form hypotheses, talk to stakeholders, bring in new sources. Bonus: the candidate names the lesson from the case (what they would do differently on the first attempt today). Honesty about the time it took (a real data anomaly is rarely cleared up in 30 minutes). Someone who has never doubted their own result rarely checks enough.
BehavioralStakeholder management Describe a stakeholder request you declined or reframed. What was the original question, and what did you deliver instead?
What a strong answer surfacesBusiness judgment and the courage to question a request rather than deliver mechanically. Bonus: the candidate names the dialogue with the stakeholder (jointly reframing the question). Someone who delivers every request exactly as it comes builds many dashboards no one uses. Someone who refuses outright (that's the wrong question) with no proposal shows an arrogant posture that quickly leads to conflict at an SMB.
SituationalStakeholder management A sales lead asks you for an ad-hoc analysis that, in your estimate, takes 2 days. They want it this afternoon. How do you react?
What a strong answer surfacesClarifying the need before negotiating the timeline: which decision is the analysis meant for, what level of detail is enough. Offering options: a simple version today, the complete version in 2 days; a scope cut; pointing to an existing dashboard. Someone who just says yes and delivers something half-baked the same day builds in data-quality problems. Someone who refuses outright shows weak stakeholder management.
SituationalData scrutiny and investigation In the weekly analysis you discover a sudden change in a key metric (conversion drops 20 % in one week). What do you do in the next 24 hours?
What a strong answer surfacesA structured investigation: (1) check the data quality and instrumentation (the most common cause), (2) segment (new vs. existing users, device, source, region), (3) talk to the affected functions (was there a release, a campaign change, a third-party outage), (4) share prioritized hypotheses with stakeholders. Someone who immediately alarms management without checking creates a false alarm. Someone who waits and watches misses the window to react.
SituationalPrioritization and trade-off Three functions (sales, marketing, product) ask you for large analysis projects in the same quarter. You can only do two of them. How do you prioritize?
What a strong answer surfacesAn explicit prioritization framework: business impact per hour of effort, the strategic importance of the topic, the existence of other sources for the deferred request. Expected method: talk to the three functions to understand the real need behind the request, prioritize together with the manager, give transparent feedback. Someone who prioritizes simply by the requester's rank (management first) shows weak business judgment. Someone who picks two projects without consultation builds in conflict.
CaseAnalytical method Our SaaS product has a 30-day activation rate of 35 %. The team wants to understand what most strongly influences the probability of activation. How do you proceed analytically?
What a strong answer surfacesA structured approach: (1) sharpen the activation definition (which concrete step counts as activation), (2) instrument the funnel and identify the most costly drop-off points, (3) build cohorts (by acquisition source, onboarding variant, segment), (4) descriptive analysis before any modeling (logistic regression or similar comes only when the question requires it). Bonus: the candidate distinguishes correlation from causation and proposes an experiment to validate an identified hypothesis. Someone who immediately talks about machine learning or a random-forest model without framing the funnel shows a method weakness.
CaseData scrutiny and investigation Debug: your weekly report has shown strangely stable conversion numbers for 3 weeks, even though marketing spend and the product release have changed a lot. How do you proceed?
What a strong answer surfacesStructured data scrutiny: (1) check the data sources (is the tracking running, has an API change distorted the event volume), (2) manually check samples (does a single conversion match what is in the CRM or logs), (3) talk to the developers (was there a silent bug in the tracking layer), (4) pull historical comparison values from alternative sources. Someone who just reports the numbers without questioning builds blind trust in faulty data. Bonus: the candidate recognizes that overly stable numbers are often a stronger warning signal than chaotic ones.
CaseAnalytical method Task: you are to deliver the CFO a forecast for the ARR trajectory over the next 6 months. What data do you need, which method do you choose, and what uncertainty do you communicate?
What a strong answer surfacesClarification before the method: which assumptions on acquisition, churn, expansion; which level of detail per segment. Method: a simple cohort projection with churn and expansion rates, sense-checked against historical data; not necessarily an ML model. Bonus: the candidate delivers scenarios (best, base, worst case) instead of a point estimate and names the sensitivity to 1 to 2 key assumptions. Someone who jumps into a complex time-series analysis without clarifying shows no feel for the stakeholder's need.
TechnicalSQL and tooling solidity SQL: you have a table events(user_id, event_name, occurred_at). How do you write a query that returns, for each user, the time between sign-up and first purchase?
What a strong answer surfacesCommand of window functions or self-joins, CTEs for readability, correct handling of users with no purchase (LEFT JOIN, NULL handling), aggregation at the right granularity. Bonus: the candidate asks whether sign-up and purchase are in the same table, whether multiple purchases occur, which time-zone convention applies. Someone who writes a query straight away without clarifying that does not run on a typical data structure shows weak practice. Someone who uses no CTE or window function and works with nested subqueries is usually at a lower SQL level.
TechnicalBusiness orientation Which metrics do you recommend for a B2B SaaS SMB's weekly business review? Why these and not others?
What a strong answer surfacesA healthy cadence logic: leading indicators (qualified pipeline, activation rate, trial-to-paid conversion) for ongoing steering, lagging indicators (MRR, ARR, Net Revenue Retention, churn) for strategic assessment. Bonus: the candidate distinguishes operational from strategic metrics and adapts the set to the company's stage (a seed-stage SMB does not watch the same things as a Series B scale-up). Someone who lists 15 metrics with no hierarchy has never owned real steering.
TechnicalAnalytical method Explain the difference between correlation and causation with a concrete business example. How would you validate a suspected causation?
What a strong answer surfacesA clear conceptual understanding: correlation can be observed, causation can only be plausibly established in a controlled experiment or via quasi-experimental methods (difference-in-differences, regression discontinuity, instrumental variables). Bonus: the candidate names a concrete business example (e.g. users who read our guide churn less does not mean the guide prevents the cancellation; maybe engaged users are more loyal anyway). Someone who cannot articulate the difference clearly will often sell spurious effects as causal in analyses.
ValuesStakeholder management How do you react when a stakeholder asks you for an analysis that, in your estimate, is meant to justify a decision already made after the fact?
What a strong answer surfacesIntegrity and business judgment. Bonus: the candidate describes a concrete case where they reframed the question to deliver an honest analysis (instead of either delivering mechanically or refusing confrontationally). Someone who simply says I deliver what is ordered shows an order-taker posture with no business partnership. Someone who refuses outright shows a weakness in the stakeholder relationship. The healthy answer lies in dialogue.
ValuesMentoring and knowledge sharing What role do you play in a team's data culture? Describe a situation where you upskilled a colleague in handling data.
What a strong answer surfacesAn active mentoring posture: training in SQL or in reading dashboards, documenting common pitfalls, pedagogical reviews of requests. Someone who says I help when asked, with no more concrete detail, shows a passive posture. At an SMB with a small data team, the ability to carry the data culture more broadly is decisive for the sustainability of the analytics function.
ValuesCoachability What criticism of one of your own analyses did you receive most recently that you initially thought was wrong, and what changed your mind?
What a strong answer surfacesOpenness to criticism and an ability to learn. Bonus: the candidate names the concrete trigger of the change of mind (an alternative data source, a sample check, a methodological argument). Someone who describes having explained their own logic to the critic instead of listening shows a coachability weakness. At an SMB where the analyst often works alone, the ability to actively seek criticism is a hard quality signal.
Evaluation playbook
The Data Analyst role reveals itself across five evaluation stages. The SQL practical exercise (stage 3) is the most telling stage: here the analyst with real practice separates from the one who only talked about dashboards. Keep the task realistic and under 2 hours, or you filter out the best profiles.
Stage 1: CV review
Look for concrete business impact, not just tools. An analyst who writes SQL, Python, Tableau without naming a concrete outcome (improved a conversion funnel by X points, introduced monthly forecasting in the sales team, identified churn drivers) has usually maintained dashboards, not supported decisions. Stack consistency (at least 12 to 18 months on a similar stack) matters more than a long tool list. An academic background (statistics, economics, computer science) helps but is not mandatory; good self-taught profiles with a bootcamp background (Le Wagon Data, Spiced, neue fische) often deliver stronger business orientation than pure quant graduates.
Stage 2: Phone screen (30 min)
Three questions only: (1) Describe an analysis that changed a concrete business decision. What was the question, what did you find, what was decided? (2) Which stakeholder request did you last decline or reframe? (business judgment and courage), (3) Why a change now? Outcome: go/no-go in a 5-minute debrief. Avoid technical gotcha questions on SQL syntax or statistics terms at this stage; look for business thinking.
Stage 3: SQL practical exercise (90 min)
A bounded, realistic task on a sample dataset: 3 to 5 business questions to be answered with SQL (e.g. conversion-funnel analysis, cohort retention, uncovering an anomaly pattern). Important: the candidate may use documentation and the internet; assess the quality of the queries (CTEs, window functions, joins), the clarity of the reasoning and the translation into business recommendations. Avoid pure algorithm tasks with no business relevance. Bonus: the candidate questions the data quality or the framing of the question before computing.
Stage 4: Stakeholder simulation (60 min)
A role-play with a PM, sales lead or manager: the candidate presents the results of the SQL task to a stakeholder who is short on time and wants only the key findings. Assess: structuring the message (the answer first, then the method), adapting to the stakeholder's vocabulary, handling critical follow-up questions, acknowledging zones of uncertainty. This is the most predictive stage for business orientation and cross-functional communication, which weigh more at an SMB than pure tool mastery.
Stage 5: References (structured check)
Call two references: a former manager (Head of Data, CFO, COO) and a former stakeholder from a business function (sales, marketing, product). Ask both the same 4 questions: What is she/he strongest at? Where would you hire someone complementary? Would you hire them again tomorrow, why? A concrete example of an analysis that changed a decision? The stakeholder reference delivers the real business-impact signal, which a manager often smooths over.
How to recognize a great hire
| Trait | Below bar | On bar | Above bar |
|---|---|---|---|
| Business orientation | Delivers mechanically what is ordered, without questioning the underlying need. Describes projects through tools and methods, not through decisions made. Confuses reporting with analysis. | Clarifies, before the analysis, which decision it is meant for. Structures the answer along the business question. Can explain their own analyses to a non-technical stakeholder in 5 minutes. | Actively drives the business question forward: proposes analyses stakeholders did not request, identifies blind spots in steering, translates data findings into decision recommendations. Seen by business functions as a sparring partner, not a supplier. |
| SQL and tooling solidity | Stumbles over advanced SQL (window functions, CTEs, correct joins). Builds slow or unreadable queries. Commands a BI tool only superficially (drag-and-drop, no custom metrics). | Writes clean, readable SQL with CTEs and window functions. Commands at least one BI tool (Looker, Tableau, Power BI, Metabase) at the custom-metrics level. Can use Python or R for ad-hoc analyses where SQL hits its limits. | A reference on the team for SQL and tool quality: documents reusable patterns, automates recurring analyses via dbt or an equivalent, upskills colleagues in tool use. Recognizes when a question exceeds SQL and requires Python or a statistics model. |
| Analytical method | Jumps from the question straight into a complex method (machine learning, time-series model) without laying descriptive foundations. Confuses correlation with causation. Rarely questions their own assumptions. | Frames the question before the method. Begins with descriptive analysis before modeling. Separates correlation from causation explicitly. Recognizes their own assumptions and names them in communication. | Chooses the simplest method that answers the question, and justifies the choice. Proposes experiments or quasi-experimental designs to validate suspected causations. Delivers scenarios and sensitivities instead of point estimates when the uncertainty requires it. |
| Data scrutiny and investigation | Trusts the data blindly. Does not recognize anomalies or escalates them with no own investigation. Reacts to strangely stable numbers with relief instead of suspicion. | Checks the data quality before every analysis. Recognizes anomalies and investigates them in a structured way (segmentation, source check, samples). Actively talks to developers and affected functions to clear up data errors. | Establishes a data-quality culture on the team: documents known pitfalls, builds automatic consistency checks, trains colleagues in critically reading dashboards. Recognizes systemic data-quality problems and prioritizes fixing them in the infrastructure. |
| Stakeholder management | Delivers mechanically what is ordered, or refuses confrontationally. Communicates technically with no adaptation to the stakeholder. Conflicts with business functions recur. | Clarifies requests before execution. Adapts language and level of detail to the stakeholder. Can reframe a request without damaging the relationship. | Is actively brought into the framing by business functions, not only for execution. Facilitates data-based decision meetings, keeps the focus on the business question and translates between analytical and operational vocabulary. |
| Coachability | Defends their own analysis instead of examining criticism. Rarely seeks feedback actively. Repeats the same mistakes across several projects. | Takes criticism in a structured way, examines it against data and adjusts the analysis when the criticism lands. Actively seeks reviews on complex projects. | Systematically seeks reviews and critical counter-voices before publishing an analysis. Documents lessons from earlier mistakes for the team. Actively trains younger profiles in taking criticism. |
30 / 60 / 90 day success plan
By day 30
- Access to all data sources (data warehouse, BI tool, product analytics, CRM) set up and validated with a sample query
- Weekly 1:1s established with the 3 to 5 most important stakeholders (management, sales lead, marketing lead, product lead)
- Audit of the existing dashboards and reports: which are actually used, which are orphaned, which contain contradictory definitions
- First independent ad-hoc analysis delivered with a documented method and a business recommendation
By day 60
- Weekly or biweekly business review established with a consolidated metric set, or an existing one sharpened
- First structural analysis (funnel analysis, cohort retention, forecast or equivalent) completed and presented with a recommendation to management
- At least one data-quality gap identified, documented and addressed with the engineering team
- Documentation of the key metric definitions updated or newly created (activation, conversion, churn, ARR)
By day 90
- Regular delivery (2 to 4 structural analyses per month plus the business review) held consistently
- First major business decision documented as traceable to an own analysis (a pricing adjustment, an onboarding change, a segment prioritization)
- Informal mentoring of a junior profile or a business function (SQL training, a dashboard-reading workshop, data-reading support)
- Formal review with the manager: onboarding phase validated, development plan on 1 to 2 priority areas (e.g. deepening forecasting or building a dbt layer)