What is “performance”?

And what about performance makes it “web performance”?

Because performance comes in kinds. At the very least, we’ve had business performance and economic performance since long before we had the Web.

Even if you focus on a single object, you can measure all sorts of different performance for it.

For example, a car can have mechanical performance, economic performance, social performance—all different ways of looking at the same object, but each measuring how well it performs a different job. Depending on which lens you look through, you get a different definition of performance. How fast does it drive? How much money does it save me on gas? How well does it reflect my personality? Etc.

How many ways can you look at a website?

Up until Core Web Vitals, I basically thought of web performance as “site speed”: how fast does your web page load? How long does it take to render? To respond? But now that our industry is looking beyond load time metrics, introducing completely new non-time metrics—things like “stability” and “smoothness”—I can’t help but wonder…

What else should go under the “web performance” umbrella? Privacy? Security? Accessibility? Should bounce rate and conversion rate belong there too?

What is “web performance” exactly? And how is it different from other kinds of performance?

If performance is how well something works, what jobs does the Web do?

What jobs should “web performance” measure?

…and where should it stop?