How Did This Mettrix Come About?

The mettrix is kind of like a three legged stool. It's not just about the loading experience, it's about something that could theoretically happen fairly late in the lifetime of the page. With largest contentful paint, which measures how fast things get pushed in various directions, you end up with what we call "the first stepchildful paint" And then accumulative layoutship,  how much are things moving around? That those metrics would really balance each other nd and over all, show a good user experience.