In a report showing the types of devices users have been using, what qualifies as a "metric" in Google Analytics?

In Google Analytics, a "metric" refers to a quantifiable measurement that can help assess the performance of your website or app. The correct answer, indicating how many users were on mobile phones, is considered a metric because it provides a numerical representation of a specific user behavior, allowing for comparisons and analyses over time.

While the number of sessions, average session duration, and bounce rate are also valuable metrics, they provide different insights. The number of sessions measures engagement, average session duration represents the time users spend on the site, and the bounce rate indicates the percentage of sessions where users leave without interacting further. Each of these serves to enhance understanding but does not directly summarize the device usage in the same manner as the number of users on mobile phones.

Thus, the correct choice highlights a specific metric that illustrates device distribution, making it fundamental for understanding user demographics and behaviors.