What is a requirement for implementing a conversion lift test on websites?

Implementing a conversion lift test on websites necessitates having a pixel installed on the site. The pixel serves as a crucial tracking tool that captures user interactions with the website, allowing advertisers to measure conversions accurately. By embedding this pixel, businesses can gather data on how users are engaging with their site before and after exposure to ads. This data is integral to comparing the conversion rates of test groups exposed to the advertising campaign against control groups that weren't targeted, thereby assessing the effectiveness of the media buy.

The other options don't directly pertain to the requirements for a conversion lift test. High-quality video content may improve user engagement but is not essential for tracking conversions. A dedicated mobile app expands audience reach but is not required for conversion tracking on websites. Similarly, while social media login capabilities enhance user experience, they do not impact the fundamental need for a pixel to ensure accurate conversion data is collected.