What is E-E-A-T?

It's not a single score plugged directly into a ranking algorithm. It's guidance given to human raters who evaluate search results as part of testing and tuning those algorithms, and Google has been explicit that it doesn't correspond to one measurable input. It shapes ranking indirectly, through the many smaller signals that end up correlating with what raters consistently score higher.

The experience component, added most recently, specifically rewards signs of having actually done the thing rather than just researched it: a review written by someone who owns the product, a guide written by someone who has actually run the process being described. That's precisely what content written or lightly edited by a model tends to lack, since a model has read a great deal about a product but never used one.

The common mistake is treating it as a checklist: add an author bio, list some credentials, done. Raters are assessing whether the content itself demonstrates that experience and expertise. A bio sitting next to thin, generic content doesn't move the underlying assessment.