Looker Studio Interview Questions and Answers

Looker Studio is Google’s free, browser-based tool for turning data into interactive dashboards and reports. It was called Google Data Studio until October 2022, when Google renamed it Looker Studio.

Looker Studio is a free, self-service dashboarding tool for marketers and analysts. Looker is Google Cloud’s paid enterprise BI platform, built around a governed semantic model written in LookML. Looker Studio Pro is a paid version of Looker Studio with team workspaces, asset management and support.

Data sources (connections to your data), charts and tables, controls (filters such as date range and drop-down lists), pages, themes and layout settings, and sharing settings.

A data source is a reusable connection to a dataset through a connector. It defines the fields (dimensions and metrics), their types and aggregation, calculated fields and the credentials used to access the data.

A connector links Looker Studio to a data platform. Google connectors include GA4, Google Ads, Search Console, Google Sheets, BigQuery, YouTube Analytics and MySQL; hundreds of partner connectors add platforms such as Facebook Ads, LinkedIn and HubSpot.

Dimensions are categories that describe data — for example date, country or campaign. Metrics are numbers that are measured and aggregated — for example sessions, clicks or revenue.

With owner’s credentials, viewers see data through the data source owner’s access, so they do not need their own permission. With viewer’s credentials, each viewer must have access to the underlying data — useful for sensitive data.

Tables, pivot tables, scorecards, time series, bar and column, line, area, pie and donut, geo maps and Google Maps, scatter, bullet, treemap and gauge charts — plus community visualisations built by other developers.

Open lookerstudio.google.com, click Create → Report, choose a connector and authorise it, add the data source, then add charts and controls, style the report and share it.

A field you create with a formula, either in the data source or in a chart — for example CTR = Clicks / Impressions, or a CASE statement that groups campaigns into channels.

CASE WHEN REGEXP_MATCH(Campaign, ".*brand.*") THEN "Brand" WHEN Medium = "cpc" THEN "Paid search" ELSE "Other" END — it creates a new dimension based on conditions.

Parameters are user-controlled values that you can use in calculated fields — for example a target conversion rate or a currency conversion value that viewers can change in the report.

Controls let viewers interact with a report: date range control, drop-down list, fixed-size list, input box, advanced filter, slider and checkbox. They filter the charts on the page (or the whole report if made report-level).

Filters include or exclude data by conditions. You can apply them to a chart, a group of charts, a page, the whole report or the data source itself.

When cross-filtering is enabled, clicking a value in one chart (for example a country in a table) filters the other charts on the page to that value.

Drill-down lets viewers move from a summary level to more detail within the same chart — for example from year to month to day, or from country to city.

Optional metrics let viewers switch which metrics a chart displays using a selector, without the report editor creating separate charts.

Set a comparison date range on the chart or date control (previous period or previous year). Scorecards and tables then show the change as a percentage or absolute value.

Report-level components (for example a logo, header or date control) appear on every page. Page-level components appear only on the page where they are placed.

Blending combines data from up to five data sources in a single chart, joined on common dimensions (join keys) — for example Google Ads cost with GA4 key events by date and campaign.

Left outer, right outer, inner, full outer and cross joins.

Using join keys that do not match exactly (for example different date formats or campaign names), which produces missing or duplicated values. Always check the join keys first.

Use the Google Sheets connector to add a sheet as a data source. Keep the header row clean, use one table per sheet and consistent data types in each column.

It saves a snapshot of selected fields from a data source, which makes reports faster and reduces API quota errors. The extract can refresh automatically every day, week or month.

The time Looker Studio caches data before fetching it again from the source. You can change it in the data source settings and refresh manually with “Refresh data”.

The GA4 Data API has token quotas per property. Fix it by reducing the number of charts per page, using fewer complex filters, using the Extract Data connector or exporting GA4 to BigQuery and reporting from there.

Use the BigQuery connector, then choose a table or write a custom SQL query. For GA4, the free BigQuery export gives you raw event-level data.

Share with people or groups as viewers or editors, share a link (with or without sign-in), embed the report on a website, download it as a PDF or schedule email delivery.

Use Share → Schedule delivery to send a PDF of the report to recipients daily, weekly or monthly at a set time.

Enable embedding in File → Embed report, then copy the iframe code into your web page. Viewers also need access to the data unless you use owner’s credentials.

A ready-made report you copy and connect to your own data source. Looker Studio includes a template gallery, and you can make any report into a template for your team.

Start with the business question, put key KPIs as scorecards at the top, use consistent colours and date ranges, limit each page to a few charts, label metrics clearly, and add controls so viewers can filter by themselves.

Reduce the number of charts and blends per page, use the Extract Data connector or BigQuery, limit date ranges, avoid heavy calculated fields in charts and increase data freshness intervals.

Agree on the KPIs, connect GA4, Google Ads, Meta Ads (partner connector) and Search Console, blend cost and key events by date and campaign, add scorecards with period comparison, trend charts, channel and campaign tables, and a date control, then schedule a weekly email.

Looker Studio is free, fully browser-based and integrates natively with Google products, making it ideal for marketing reporting. Tableau and Power BI are paid BI tools with stronger data modelling and enterprise features.

LookML is Looker’s modelling language. It describes dimensions, measures, calculations and table relationships so that Looker can generate SQL queries consistently for everyone.

An Explore is the starting point for queries in Looker. It is defined in a model file, built on a view and can join other views.

Looks are saved single visualisations or queries in Looker that can be shared and added to dashboards.

A derived table is a query whose results are used like a database table. It can be written in SQL (SQL derived table) or defined from an Explore (native derived table, NDT). Persistent derived tables (PDTs) are written to the database for speed.

Pre-built LookML models and dashboards for common data sources and analyses, which teams can use as a starting point.

Yes. Looker generates SQL from the LookML model and runs it directly against the database, such as BigQuery, Snowflake or Redshift — it does not copy the data into its own storage.