Hello, and welcome to another episode of Weekly Wisdom with me, Bartosz Góralewicz. Today I want to explain and briefly touch on how the concept of real user metrics and the way we measure performance change in 2019 and beyond.
Real user metrics are basically the opposite of the page load time and how we measured that for years in the SEO and web performance community. If we compare the page load, like load time from, for example, GTmetrix, it doesn't really reflect a real user experience anymore.
The Problem with Synthetic Metrics
Let me give you an example, if you want to play with that, take one of the fastest websites out there, like The Guardian, look at the performance of The Guardian in GTmetrix and compare that with how you perceive that performance on even like a slower mobile, with low-end CPU or your laptop.
You will see a massive difference between that experience you had, real user experience and the metrics you get from tools set like GTmetrix.
This is where real user metrics, RUM in short, actually come in and play a very, very important role in how web development evolves in 2019 and beyond.
Real user metrics actually divide your website loading experience into different stages. They allow both you and the search engines when evaluating your performance, to see different moments of when your website loads, when you can actually interact with the website or when you can receive the information you are looking at.
One of my favorite examples is when you are looking for the weather in London tomorrow. Obviously you can get that data directly from Google now, but when you open your favorite weather website like accuweather.com; the only information that is actually valuable for you is the weather in London tomorrow.
This is the difference between when the website is fully loaded and when you actually got the information that you cared about the most.
In this scenario, the metric you are looking at is called First Meaningful Paint. You are looking for it, meaning that in our example of AccuWeather- you what the weather is going to be in London tomorrow, plus if it is going to rain, the degrees, if it is going to be 20 degrees weather, or if you are in the states and prefer Fahrenheit, that is what you are going to see. So this is going to be what you are looking for on that website.
Here comes the tricky part because this metric is very difficult to measure on a scale. First Meaningful Paint is different for each website, so if you are looking for the weather, this is fairly simple; you are looking for degrees and if it is going to rain or not. But if you are going to a site like giphy.com, you are going to want to see different GIFs that you can choose from. That is going to be your meaningful paint — the GIFs you are looking for. But if you are looking for an article, for example on The Guardian, the most important part of the website you are looking for, to be loaded, is the title of the website.
What are the Real User Metrics
Just to simplify, there is a difference between load time and real user metrics. In this example, the load time basically checks how fast the whole website is going to load, but in regards to how web development changes and because we serve some of the elements of the website sooner, we are looking at the real user metrics.
I won't go in-depth into different metrics you can measure. The two most important ones are First Meaningful Paint, which, again is very difficult to measure on a scale, and the new metric that is just evolving recently is the Largest Contentful Paint. Just look at these two. You can get them from Chrome User Experience Report, CrUX, and we will link to that here in the video. Play with that and I will get deeper into the topic in my next video. Thank you so much and stay tuned for more weekly wisdom.