Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About EXL hiring for Power BI roles
EXL is a data analytics and digital operations company serving insurance, healthcare, banking and other industries. Its analytics teams build models for risk, marketing, collections and claims. In India it hires for business analysts, data analysts, data scientists and operations roles, many of them in insurance and banking analytics.
For Power BI roles, this EXL practice set focuses most on Power Query and Data Transformation (7), Power BI Fundamentals (7), Advanced DAX and Time Intelligence (5), Performance Optimisation and Administration (4). It has 9 easy, 17 medium, 4 hard questions, so you can start easy and work up to the harder ones.
Company type
Analytics
Headquarters
New York, USA
Main India offices
Noida, Gurugram, Bengaluru, Pune
EXL Power BI interview process
Online assessment (aptitude + SQL or analytics)
Technical interview
Case or guesstimate round
HR round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
Solved for EXLStart practicing
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01
How do you control how visuals interact with each other?
By default, selecting a data point cross-filters or cross-highlights other visuals on the page. Use Format, Edit interactions to choose filter, highlight or none for each visual pair, for example stopping a slicer from affecting a target KPI card. Slicers can also be synced across pages with the Sync slicers pane. Clear interaction design prevents confusing behaviour.
let
StartDate = #date(2022, 1, 1),
EndDate = #date(2026, 12, 31),
Days = Duration.Days(EndDate - StartDate) + 1,
Dates = List.Dates(StartDate, Days, #duration(1, 0, 0, 0)),
T = Table.FromList(Dates, Splitter.SplitByNothing(), {"Date"}),
Typed = Table.TransformColumnTypes(T, {{"Date", type date}}),
Y = Table.AddColumn(Typed, "Year", each Date.Year([Date]), Int64.Type),
M = Table.AddColumn(Y, "Month", each Date.MonthName([Date]), type text)
in
M
03
Why should you set data types correctly in Power Query?
Correct data types make sorting, filtering, aggregation and relationships work properly; text-typed numbers cannot be summed and mismatched key types break relationships. Types also affect compression and model size, for example whole numbers compress better than decimals or text. Set types once near the end of a query and avoid repeated automatic Changed Type steps, which can fail when column names change.
04
Sales data has region codes, while targets use region names. How do you combine them?
I would create or import a region mapping table with code and name, clean both sides by trimming spaces and fixing case, then merge in Power Query or better, build a Region dimension table with both columns and relate sales by code and targets by name to it. Unmatched rows should be checked using a left anti join so missing mappings are fixed rather than silently dropped.
05
Describe a time you cleaned very messy data under a deadline.
Situation: a client sent 36 monthly Excel files with merged headers and changing columns two days before a review. Task: build a consolidated sales report. Action: I used the Folder connector with a custom function that promoted the right header row, unpivoted month columns and mapped renamed fields through a lookup table. Result: the report was ready a day early, and future files loaded automatically with no manual work.
Power BI Project (PBIP) saves a report and model as folders of text files instead of one binary PBIX file. The semantic model is stored in TMDL or TMSL and the report in JSON definitions. This makes Git version control, code reviews, diffs and merge of changes practical, and works with Fabric Git integration and deployment pipelines. It is preferred for team development and CI/CD.
07
A source table has duplicate customer rows with different spellings of the same name. What do you do?
For exact duplicates, Remove Duplicates on the key column. For spelling variations, use fuzzy matching in Merge Queries with a similarity threshold and transformation table, review results, and maintain a mapping table of approved matches. The best long-term fix is to use a stable customer ID from the source system and report data quality issues to the owner rather than cleaning endlessly in Power BI.
08
What are paginated reports and when would you use them?
Paginated reports, built with Power BI Report Builder, are pixel-perfect, print-ready reports that can span many pages, such as invoices, statements or regulatory reports with long tables. They are ideal when users need exact layout, export to PDF or Excel, or detailed row-level listings. Interactive Power BI reports are better for exploration. Paginated reports can run in the Service with Pro, PPU or Fabric capacity.
09
How does the VertiPaq engine store and compress data?
VertiPaq is the in-memory columnar engine for Import models. It stores each column separately and compresses it using dictionary encoding, which maps unique values to integers, value encoding for numbers, and run-length encoding for repeated sequences. Compression depends mostly on column cardinality, so columns with few unique values compress very well, while unique IDs and precise timestamps take most of the memory.
10
What is an on-premises data gateway and when is it needed?
The on-premises data gateway is software installed on a machine inside the company network that securely connects the Power BI Service to on-premises sources such as SQL Server, file shares or Oracle. It is needed for scheduled refresh and DirectQuery to those sources. Standard mode supports many users and is centrally managed; personal mode is for a single user. Cloud sources usually do not need a gateway.
11
Your measure using IF and many nested CALCULATE calls is slow. How do you optimise it?
I would store repeated sub-expressions in variables so they are computed once, replace nested IF chains with SWITCH(TRUE(), ...), use column filters instead of FILTER over tables, and avoid context transition inside large iterators. I would also check whether some logic can move into a calculated column or Power Query at refresh time. DAX Studio timings confirm whether formula engine time drops.
12
A YTD measure returns blank for future months on a chart. Users want the line to stop at today. How?
The issue is the opposite for many teams: YTD repeats the last value for future months. I would add a condition so the measure returns BLANK when the period starts after the last date with data, for example IF(MIN('Date'[Date]) > [Last Sales Date], BLANK(), TOTALYTD(...)). Alternatively add a column flagging dates up to today in the date table and filter the visual on it.
13
Write a measure that shows the selected slicer value in a title.
Report Title =
VAR r = SELECTEDVALUE('Store'[Region], "All Regions")
VAR y = SELECTEDVALUE('Date'[Fiscal Year], "All Years")
RETURN "Sales for " & r & " - " & y
Use it in a visual title through conditional formatting, Title text, Field value. SELECTEDVALUE returns the fallback text when zero or multiple values are selected.
14
What modelling practices reduce Power BI model size?
Remove unused columns and rows, avoid high-cardinality columns like GUIDs and datetime with seconds by splitting date and time or rounding, use integer surrogate keys, prefer measures over calculated columns, turn off Auto date/time, and choose the right data types, such as fixed decimal. Load only the history users need, and summarise data where detail is not required.
A semantic model, earlier called a dataset, is the published data model behind reports: tables, relationships, measures, hierarchies, security roles and refresh settings. Many reports can connect to one shared semantic model, which keeps business logic and numbers consistent across teams. Certified or promoted endorsements help users find trusted models. Build permission controls who can create new reports on it.
16
Business wants year-over-year growth, but the current year is incomplete. How do you compare fairly?
Comparing a partial year with a full last year understates growth. I would limit last year to the same date range, for example using the last date with sales this year and filtering last year's dates up to the matching day, or compare year-to-date to previous year-to-date. I would label the visual clearly as YTD versus same period last year so readers understand it.
17
Explain the typical Power BI workflow from data to insight.
First connect to sources such as Excel, SQL Server or SharePoint and clean the data in Power Query. Then build a data model with relationships, ideally a star schema, and write DAX measures. Next design report visuals and interactions in Desktop. Publish to a workspace in the Power BI Service, set scheduled refresh through a gateway if needed, apply row-level security and share through an app or dashboard.
18
Your organisation has 500 report viewers. How would you plan licensing?
Giving all 500 viewers Pro licences is one option. If there are many viewers and heavy models, Fabric capacity at F64 or above lets free-licence users view content in workspaces on that capacity, while report creators still need Pro or PPU. I would compare costs, workload size and features like larger models with IT, and recommend the option that fits usage, without assuming one choice fits all.
19
Tell me about a time you had to deliver a report with unclear requirements.
Situation: an operations head asked for a 'delivery performance dashboard' with no detail. Task: deliver something useful in a week. Action: I held a 30-minute session to list five questions they wanted answered, sketched a page layout and built a quick prototype in two days with sample data. After feedback I finalised it. Result: the dashboard went live on time and became part of the weekly operations review.
20
What is a disconnected table and how is it used for what-if analysis?
A disconnected table has no relationship to the model and is used to capture a user's choice through a slicer. For example, a Discount table from 0 to 30 percent created with GENERATESERIES, or the What-if parameter feature, lets a measure read SELECTEDVALUE(Discount[Value]) and calculate projected revenue. Since it does not filter facts, the measure decides how the selection is applied.
21
A stakeholder insists on a 3D pie chart with 12 slices. How do you handle it?
I would understand what they want to see, usually share of total by category, then show a quick comparison: a sorted bar chart beside the pie, explaining that bars make small differences readable while 3D distorts sizes. Offering a donut with top five plus Others is a compromise. Usually seeing both side by side convinces them, and the final choice remains theirs.
22
Two queries return the same data from different systems, and totals do not match. How do you investigate?
I would compare row counts and totals at a high level first, then drill down by date and key dimensions to find where the difference starts. Merge both tables with a full outer join on the business key and use anti joins to list missing rows, then compare values on matched rows. Common causes are different cut-off times, filters, duplicates, time zones or currency conversions.
Situation: a finance report took 40 seconds per page with a 2 GB file built on joined flat tables. Task: improve speed. Action: I split it into a star schema with Date, Account, Cost Centre and fact tables, removed unused columns, turned off auto date/time and replaced bi-directional filters with single direction. Result: model size dropped to 450 MB and pages loaded in under 4 seconds.
24
Each regional manager must see only their region, and the CEO must see everything. How do you implement this?
I would build dynamic RLS with a security table of Email and Region, related to the Region dimension, and a role filter Security[Email] = USERPRINCIPALNAME(). The CEO and other full-access users get an 'All' flag handled in the rule, or are placed in a separate role with no filter. I would test with View as role in Desktop and in the Service before publishing the app.
KEEPFILTERS changes how a CALCULATE filter argument combines with the existing filter context: instead of replacing filters on that column, it intersects with them. For example, CALCULATE([Sales], KEEPFILTERS('Product'[Color] = "Red")) shows blank for Blue rows in a colour table, while without KEEPFILTERS every row would show Red sales. It is useful for measures that should respect user selections.
26
How do you design a KPI card that shows value, target and variance?
Use the new Card visual or a KPI visual with a main measure such as Total Sales, a target measure and a variance percent measure. Add conditional formatting so the variance turns red below target and green above it, and include a small trend if space allows. Keep labels short, such as Sales vs Target, and show the comparison period in the subtitle.
Best Practice Analyzer, in Tabular Editor and also available in Fabric notebooks through semantic link labs, scans a semantic model against a set of rules, such as avoiding bi-directional relationships, hiding foreign keys, not summarising numeric IDs, using DIVIDE, and setting format strings. It lists violations with their severity so teams can fix them before release. Rules can be customised to match team standards.
28
Your calculated columns have made the model huge. What do you do?
I would move simple row-level logic into Power Query or the source SQL, where it compresses better and can fold, and replace aggregations stored as columns with measures. High-cardinality columns such as concatenated keys or precise timestamps should be removed or split. Then check model size with VertiPaq Analyzer in DAX Studio to confirm which columns used the most memory.
29
What is a Power BI workspace and what roles does it have?
A workspace is a container in the Power BI Service for semantic models, reports, dashboards, dataflows and other items that a team works on together. Roles are Admin, Member, Contributor and Viewer. Admins manage everything including access, Members can publish and share, Contributors can create and edit content but not share, and Viewers can only view. Consumers are usually given access through an app instead.
30
How do you handle a business user who keeps changing report requirements?
I first understand the goal behind the changes, because frequent changes often mean the core question was not clear. I write down agreed requirements and a mock-up, then deliver in small iterations so feedback comes early. In one project weekly 20-minute reviews cut rework a lot, and changes that were large were logged for the next version rather than added mid-sprint.
Tips to crack the EXL Power BI interview
Revise SQL, Excel and statistics such as hypothesis testing and regression, which are core to EXL analytics roles.
Practise guesstimates and simple business cases about credit card customers or insurance claims.
Learn insurance and banking analytics concepts like loss ratio, churn and collections propensity models.
Keep a one-minute story ready for every project on your CV: problem, your part, tools, result.
Practise the hard questions on this page aloud; EXL interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the EXL Power BI interview?
Candidates usually go through 4 stages: Online assessment (aptitude + SQL or analytics); Technical interview; Case or guesstimate round; HR round. The exact rounds change with the role, team, location and your experience, so confirm the process with the recruiter.
Which topics should I prepare for the EXL Power BI interview?
This practice set leans on Power Query and Data Transformation (7), Power BI Fundamentals (7), Advanced DAX and Time Intelligence (5), Performance Optimisation and Administration (4). Revise those first, then practise explaining one or two of your own projects end to end, because most EXL interviewers ask you to walk through real work.
Are these the exact questions asked at EXL?
No. These are curated practice questions that match the skills and difficulty usually tested in analytics interviews like EXL's. They are not a leaked or verified list of past questions.
Where does EXL hire Power BI professionals in India?
EXL has large teams in Noida, Gurugram, Bengaluru, Pune. Openings and locations change often, so check the EXL careers page and filter by city and experience.