Track a 'Request a Demo' button click

WHAT THIS TESTS: This question checks whether you understand the full pipeline of event instrumentation, not just dropping a script on a page. The interviewer wants to see that you can distinguish between automatically collected events, enhanced measurement, recommended events, and custom events, and that you know how to capture contextual data so the product manager can actually segment the report by blog post or button variant.

A GOOD ANSWER COVERS: First, selecting the right event type. Because Request a Demo is not automatically collected, you should explain that enhanced measurement might catch outbound clicks but not this specific button reliably, so a custom event is appropriate. Second, frontend capture. You would add an event listener to the button element, perhaps using a data attribute like data-track-id to keep analytics logic separate from styling. Third, payload construction. The payload should include the event name such as request_demo, a timestamp, the page location, and custom parameters like button_text or blog_post_slug so the PM can filter reports. Fourth, transport. You would send this via gtag with the event command if using gtag.js, ensuring the call sits below the Google tag snippet, or push it to the dataLayer for Google Tag Manager. Fifth, validation. Mention checking the Realtime or DebugView reports to confirm the event arrives before the code ships.

COMMON WRONG ANSWERS: A major red flag is suggesting a pageview-based workaround, such as sending the user to a thank-you page and counting visits there as clicks. Another is using a generic click event without parameters, which makes it impossible to tell this button apart from every other button on the site. Some candidates forget to mention that the gtag function must be placed after the base Google tag loads, which means the event call will fail silently if inserted too early. Also, proposing to track every click on the page rather than scoping to the specific button shows poor data hygiene.

LIKELY FOLLOW-UPS: The interviewer might ask how you would handle single page applications where the blog post loads dynamically, or how to debounce rapid clicks to avoid duplicate events. They could also ask about privacy compliance, such as respecting consent mode before firing the event, or how you would A/B test two different button labels while keeping the same event name and varying a custom parameter.

ONE CONCRETE EXAMPLE: Suppose the blog post lives at example.com/blog/productivity-tips. The button has an ID of demo-cta and displays the text Get a Free Demo. In your JavaScript, you select the button and add a click listener. Inside the handler, you call gtag with the event command, passing event name request_demo and parameters page_location set to the current URL, button_text set to Get a Free Demo, and content_group set to blog. You then open the DebugView report in Google Analytics, click the button, and verify that request_demo appears with the correct parameters within 30 seconds.

Source: developers.google.com