What is an example of a fallback metric in web application settings?

A fallback metric in web application settings serves as an alternative measure when more specific metrics may not be available or relevant. In this context, the option of Frustrating Load Time (defined as load times exceeding 12 seconds) represents a critical usability threshold. This metric provides insight into user experience, helping teams understand when performance is sufficiently poor to be considered unacceptable.

When the typical load time metrics cannot capture the performance perception adequately, such as during extreme cases of slowness, Frustrating Load Time serves as a fallback. It identifies situations where user patience is likely to be tested, helping to prioritize optimizations.

Other metrics like Time to First Byte, Load Event Start, and Speed Index are important performance indicators but do not specifically relate to user frustration thresholds in the same way. They offer insights into various stages of the loading process or overall performance but do not inherently signal an unacceptable user experience when load times drag excessively. Thus, the option highlighting Frustrating Load Time as a fallback metric effectively addresses scenarios where user experience becomes critically compromised.