Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About Cognizant hiring for Power BI roles
Cognizant is a US-headquartered IT services and consulting company with most of its workforce based in India. It provides application development, testing, cloud, digital engineering and data analytics services, with strong practices in healthcare, insurance and banking. In India it hires for programmer analyst, quality engineer and data roles through campus and off-campus programmes such as GenC.
For Power BI roles, this Cognizant practice set focuses most on Performance Optimisation and Administration (5), DAX Fundamentals (5), Power BI Service, Sharing and Security (4), Visualisation and Report Design (4). It has 14 easy, 16 medium questions, so you can start easy and work up to the harder ones.
Company type
IT services
Headquarters
Teaneck, New Jersey, USA
Main India offices
Chennai, Bengaluru, Pune, Hyderabad, Kolkata
Cognizant Power BI interview process
Online assessment (aptitude + reasoning)
Coding assessment
Technical interview
HR round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
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01
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.
02
Leadership wants to see a red, amber, green status for each region against target. How do you build it?
I would create a measure for achievement percentage, DIVIDE(Sales, Target), and a status measure returning a colour or icon based on thresholds agreed with leadership, such as below 90 percent red, 90 to 100 amber, above 100 green. Apply it through conditional formatting in a matrix or as icon rules. I would also add text or icons so status is clear without colour.
03
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.
04
How do you set up scheduled refresh in the Power BI Service?
Open the workspace, select the semantic model's settings, and check Data source credentials and Gateway connection, mapping on-premises sources to a gateway. Then turn on Scheduled refresh, choose time zone, frequency and time slots, and add failure notification contacts. Pro allows up to 8 refreshes per day and Premium or Fabric capacity up to 48. Stagger refresh times to avoid source load peaks.
05
How do you stay current with frequent Power BI updates?
Power BI releases features monthly, so I read the monthly update blog and Fabric release notes, try new features on a test report, and follow community experts and forums. I keep a short list of features relevant to our team, such as visual calculations or TMDL view, and share a five-minute demo in team meetings when something will save us effort.
06
Why should you use DIVIDE instead of the division operator?
DIVIDE(numerator, denominator, alternate) handles division by zero and blank denominators safely, returning blank or the alternate value instead of an error or infinity. It makes measures like margin percentage cleaner without IF checks. The division operator is slightly faster when you are certain the denominator is never zero, but DIVIDE is the safer default in reports.
07
Rewrite a slow measure to use variables and avoid repeated calculation.
Before:
Growth = IF([Sales PY] = 0, BLANK(), ([Total Sales] - [Sales PY]) / [Sales PY])
After:
Growth =
VAR cur = [Total Sales]
VAR py = [Sales PY]
RETURN DIVIDE(cur - py, py)
The previous year measure is now evaluated once instead of three times, and DIVIDE handles zero safely.
08
Write a measure for sales of a specific category and region.
Electronics North Sales =
CALCULATE(
[Total Sales],
'Product'[Category] = "Electronics",
'Store'[Region] = "North"
)
Multiple filter arguments are combined with AND. Wrap a filter with KEEPFILTERS if it should intersect with an existing slicer selection instead of replacing it.
09
Write basic measures for total sales, total cost and profit margin percentage.
Total Sales = SUM(Sales[Amount])
Total Cost = SUMX(Sales, Sales[Qty] * Sales[UnitCost])
Profit = [Total Sales] - [Total Cost]
Margin % = DIVIDE([Profit], [Total Sales])
Format Margin % as a percentage. Building measures on other measures keeps logic in one place and easy to change.
10
How do you set up an app with different audiences?
In the workspace choose Create app or Update app, add the reports and dashboards, then in the Audience tab create audiences such as Sales Managers and Finance, choose which content each audience sees and grant access to the right Entra ID security groups. Publish the app and share the link. Remember RLS still controls rows inside reports; audiences only control which items are visible.
11
What is the difference between Merge Queries and Append Queries?
Merge is like a SQL join: it combines columns from two tables based on matching key columns, with join kinds like left outer, inner, full outer, left anti and right anti. Append stacks rows of tables with the same structure on top of each other, like a SQL UNION ALL, for example combining monthly sales files. Merge widens a table, append lengthens it.
12
What is the grain of a fact table and why does it matter?
Grain is the level of detail of one fact row, such as one row per order line per day. It must be defined clearly before building measures, because mixing grains in one table, for example daily sales and monthly targets, causes double counting and wrong totals. Facts at different grains should be separate tables related to dimensions at the matching level.
13
How do you run a DAX query in DAX Studio to test a measure?
EVALUATE
SUMMARIZECOLUMNS(
'Date'[Fiscal Year],
'Product'[Category],
"Sales", [Total Sales],
"Margin", [Margin %]
)
ORDER BY 'Date'[Fiscal Year]
Turn on Server Timings and Clear cache before running to see storage engine and formula engine time. The same EVALUATE syntax works in the DAX query view in Desktop.
Time intelligence functions compare values across periods using a proper date table, for example year-to-date, same period last year, moving averages and quarter-over-quarter growth. Key functions are TOTALYTD, DATESYTD, SAMEPERIODLASTYEAR, DATEADD, PARALLELPERIOD and DATESINPERIOD. They return sets of dates used as CALCULATE filters, so the date table must be contiguous, marked as a date table and related to the facts.
15
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.
16
What is Copilot in Power BI and what should you watch out for?
Copilot in Power BI uses generative AI to help create report pages, summarise visuals in narrative form, suggest DAX and answer questions about data in natural language. It needs supported capacity and tenant settings enabled by admins. Results depend heavily on a clean model with clear names, descriptions and synonyms, and outputs must be checked for correctness before sharing, especially generated DAX.
By default month names sort alphabetically, April first. In the Date table add a Month Number column, select the Month name column, then choose Column tools, Sort by column, Month Number. The same applies to weekday names and fiscal months. The sort column must have one value per name value, otherwise Power BI shows an error.
18
What are endorsement, sensitivity labels and lineage view?
Endorsement marks content as Promoted by its owners or Certified by authorised reviewers, guiding users to trusted semantic models. Sensitivity labels from Microsoft Purview classify content, such as Confidential, and labels flow to exports like Excel and PDF. Lineage view shows how data sources, dataflows, semantic models, reports and dashboards depend on each other, which helps impact analysis before changes.
Use sufficient colour contrast and do not rely on colour alone, for example add icons or labels to red and green. Set alt text on visuals, a logical tab order in the selection pane, clear titles and readable font sizes. Avoid tiny text and very dense pages. Power BI supports screen readers and keyboard navigation, and high-contrast themes help users with low vision.
CALCULATE evaluates an expression in a modified filter context. Its filter arguments can add, replace or remove filters, for example CALCULATE([Total Sales], 'Product'[Category] = "Electronics") replaces any category filter with Electronics. It also performs context transition when used inside a row context, turning the current row into an equivalent filter. It is the most important function in DAX.
21
What is the difference between Group By in Power Query and summarising in DAX?
Group By in Power Query aggregates rows at refresh time and stores only the summarised table, reducing model size, which is useful when detail is never needed. Summarising in DAX through measures keeps detail in the model and aggregates dynamically for any filter at query time. Use Power Query grouping for fixed summaries such as monthly snapshots, and DAX measures when users need flexible slicing.
22
Users on mobile find the report hard to read. What do you do?
I would create a mobile layout in Desktop through View, Mobile layout, placing the most important cards and charts in a single column with larger fonts. Remove or simplify dense tables, check slicer usability on touch screens and test in the Power BI mobile app. If mobile use is common, I might design a separate concise summary page for mobile users.
I like turning raw data into clear answers that people can act on. In my projects I enjoyed the full flow: cleaning messy Excel and SQL data, designing a proper model, writing DAX and making reports that users actually open every day. Power BI is widely used across Indian companies and global clients, so the role offers strong growth into data analytics, data engineering with Fabric, or BI architecture.
Visual calculations are DAX calculations defined directly on a visual and computed on the visual's own aggregated data, rather than on the model. They make running totals, moving averages, percent of parent and comparison with previous rows simpler using functions like RUNNINGSUM, MOVINGAVERAGE and PREVIOUS. They do not add measures to the model, so they suit visual-specific logic but cannot be reused across visuals.
25
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.
26
What is the difference between a report and a dashboard in Power BI?
A report is a multi-page, fully interactive document built on one semantic model, with slicers, filters, drill-through and cross-highlighting. A dashboard is a single-page canvas in the Power BI Service made of pinned tiles that can come from several reports and models; it is used for a quick at-a-glance view. Dashboards are created only in the Service, while reports are usually built in Desktop.
27
Users complain the report page is cluttered with 22 visuals. How do you redesign it?
I would ask which decisions the page supports and keep only visuals that answer those questions. Then group related KPIs into a top row of cards, keep two or three main charts, and move details to drill-through or tooltip pages. Slicers can move into a collapsible panel using bookmarks. Fewer visuals also make the page load faster.
Only one active relationship can exist between two tables along a filter path; additional relationships become inactive and appear as dashed lines. For example, Sales may have OrderDate and ShipDate both linked to Date, with OrderDate active. An inactive relationship is used only inside a measure with USERELATIONSHIP, such as CALCULATE([Sales], USERELATIONSHIP(Sales[ShipDate], 'Date'[Date])).
VAR defines a named value inside an expression and RETURN gives the final result. Variables make measures easier to read, avoid repeating the same calculation, which improves performance, and help debugging because you can return an intermediate variable. A variable is evaluated once in the context where it is defined, so its value does not change if later CALCULATE filters are applied.
30
What tools do you use to analyse Power BI performance?
Performance Analyzer in Desktop records how long each visual takes for DAX query, visual display and other work, and lets you copy the query. DAX Studio runs those queries with server timings and query plans and includes VertiPaq Analyzer for model size by table and column. Best Practice Analyzer in Tabular Editor flags modelling issues. In the Service, capacity metrics apps show load on Premium or Fabric capacity.
Tips to crack the Cognizant Power BI interview
Understand the GenC, GenC Next and GenC Elevate tracks so you know which skills and coding level each role expects.
Revise SQL queries, OOP concepts and basic testing terminology since many freshers are placed in development or QA projects.
Read about Cognizant's healthcare and life sciences domain work, which is a large part of its client base.
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; Cognizant interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the Cognizant Power BI interview?
Candidates usually go through 4 stages: Online assessment (aptitude + reasoning); Coding assessment; Technical interview; 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 Cognizant Power BI interview?
This practice set leans on Performance Optimisation and Administration (5), DAX Fundamentals (5), Power BI Service, Sharing and Security (4), Visualisation and Report Design (4). Revise those first, then practise explaining one or two of your own projects end to end, because most Cognizant interviewers ask you to walk through real work.
Are these the exact questions asked at Cognizant?
No. These are curated practice questions that match the skills and difficulty usually tested in it services interviews like Cognizant's. They are not a leaked or verified list of past questions.
Where does Cognizant hire Power BI professionals in India?
Cognizant has large teams in Chennai, Bengaluru, Pune, Hyderabad, Kolkata. Openings and locations change often, so check the Cognizant careers page and filter by city and experience.