Data analyst interview questions in English

1. Walk me through a dashboard or analysis you are proud of.

Recruiter screen

What they listen for: Business impact first, tools second. They want to hear who used it and what changed.

“The one I'm proudest of is a churn dashboard for our customer success team. Before it, they found out about at-risk accounts after they cancelled. I built it in SQL and Tableau, and within a quarter they were contacting about 30% more accounts before renewal.”

2. What is the difference between a LEFT JOIN and an INNER JOIN, and when would you use each?

SQL or technical screen

What they listen for: A correct definition and a real example of when the choice changes the answer.

“An inner join only keeps rows that match in both tables. A left join keeps every row from the left table, and fills the right side with nulls when there's no match. I'd use a left join for something like 'all users and their orders', because I don't want to lose users who haven't ordered yet.”

3. How would you find the second-highest salary in each department?

SQL or technical screen

What they listen for: Window functions, and whether you mention ties before the interviewer has to ask.

“I'd use a window function: DENSE_RANK over salary, partitioned by department, ordered descending, then filter where the rank equals two. Quick check first: if two people tie for the top salary, do you want the next distinct salary? That's why I'd pick DENSE_RANK rather than ROW_NUMBER.”

4. Daily active users dropped 15% yesterday. How would you investigate?

Case or metrics round

What they listen for: A calm, ordered process: check the data is right, then segment, then look for causes.

“First I'd check it's a real drop and not a tracking problem, for example a broken event or a late data load. If the data is fine, I'd split the drop by platform, country and app version to see where it's concentrated. Then I'd check what changed yesterday: a release, a marketing campaign ending, or an outage.”

5. How would you measure the success of a new feature?

Case or metrics round

What they listen for: One primary metric tied to the feature's goal, plus a guardrail metric that should not get worse.

“I'd start from what the feature is for. If it's meant to help people find products faster, my primary metric would be time to first add-to-cart. I'd also watch a guardrail, like return rate, to make sure we're not just pushing people to buy the wrong thing.”

6. Tell me about a time a stakeholder disagreed with your numbers.

Behavioural and stakeholder round

What they listen for: That you stayed calm, checked your work, and explained the difference in plain English.

“Our sales director told me my revenue figure was wrong, because finance reported a higher number. I didn't argue; I asked for their report and compared the definitions. Finance counted bookings, and I counted recognised revenue. I wrote a one-page note on the two definitions, and we agreed which one each dashboard should use.”

7. How do you explain a technical result to a non-technical audience?

Behavioural and stakeholder round

What they listen for: That you lead with the decision, not the method.

“I start with the answer and what it means for them, for example 'we should keep the free trial at 14 days.' Then one chart, and one sentence on how confident I am. I only explain the method if they ask.”

8. How do you handle missing or dirty data?

SQL or technical screen

What they listen for: That you look at why it is missing before you choose a fix.

“First I check why it's missing, because that decides the fix. If it's random and small, I might drop those rows. If it's missing for one group, like one country's events, dropping it would bias the result, so I'd flag it and fix the pipeline or treat it as its own segment.”

9. Tell me about a time you had to prioritise several requests at once.

Behavioural and stakeholder round

What they listen for: A clear rule for prioritising, and that you told people what you would not do.

“I had three requests in the same week. I asked each person what decision the analysis would feed into and when. Two were for a board deck on Friday, so they came first. I told the third person honestly that it would be the following Tuesday, and offered a quick number they could use in the meantime.”

10. Why do you want to be a data analyst here?

Recruiter screen

What they listen for: That you know what data problems this company has, not a general love of data.

“I've worked mostly on subscription data, and your business is subscription-first, so the questions you're asking, like retention and pricing, are exactly the ones I like. I also read that your analytics team sits inside the product teams, which is how I like to work.”

What are the most common data analyst interview questions?

Expect SQL joins and window functions, a 'metric dropped, why?' case, how you would measure a feature, how you handle messy data, and behavioural questions about stakeholders and prioritisation. In English interviews, the explanation of your SQL counts as much as the query.

How do I explain SQL out loud in an interview?

Say the table grain, the join key and the filter before you type. After you write it, say how you would check it, for example comparing row counts. Short sentences in the present tense are enough: 'I join orders to users on user ID, then group by month.'

Do I need perfect English to get a data analyst job in the UK or US?

No. You need to be clear. Interviewers care that a stakeholder can understand your finding. Clear structure, correct numbers and a confident first sentence matter far more than grammar or accent.