On the 10th of January Google rolled out an update regarding the PageSpeed Insights tool. We will fill you in on this latest update and also will answer the main question: do that scores really grade a userís true site experience?
So donít rush to paste your website URL into that input line and jump to conclusions. Bear with us to get to know if these scores matter or you are worrying unnecessarily.
What is the update about?
Google announced that PageSpeed Insights will incorporate data from the Chrome User Experience Report to provide real-world performance information for sites.
ďIn the past, these recommendations were presented without the context of how fast the page performed in the real world, which made it hard to understand when it was appropriate to apply these optimizationsĒ, Google Webmaster Central Blog claimed.
It means, every time Chrome users who have opted-in to syncing their browsing history and have usage statistic reporting enabled access your website, Google may use that data to measure its load time.
The Chrome User Experience Report has two metrics according to which the performance of your pages will be measured. One is First Contentful Paint or FCP. This metric gauge the time within which a user sees a visual response from the page. The second one is DOM Content Loaded or DCL. This one measures the time within the HTML-document has been loaded and parsed.
The PSI report now has several different elements:
By looking at the median value of FCP and DCL, Google will consider your page as Fast Ė the median value of the metric is in the top third of all page loads, Average Ė the median value is in the middle third or Slow Ė the median value is in the bottom third of all page loads.
PageSpeed Insights calculates a score from 0 to 100 that evaluates page performance headroom. It checks whether a page performance can be improved in two areas:
Time to above-the-fold load.
Itís the time from the moment a user initiates the request to the moment the above-the-fold content is displayed by the browser.
Time to full page load.
Itís the time from the moment a user initiates the request to the moment the page is fully rendered by the browser.
Based upon your performance headroom, your pages can be either Good (the page scores 80 or above), Medium (the page scores between 60 and 79), or Low (the page scores between 0 and 59).
- The Page Load Distributions
This section presents how FCP and DCL events are distributed in the data set. These events are categorized as Fast (top third), Average (middle third), and Slow (bottom third) by comparing to all events in the Chrome User Experience Report.
This section indicates if the page might be faster by modifying the appearance and functionality of the page.
It will surprise you, but there is hardly a correspondence between the Google scores and the website performance. How come?
The true story
Have you ever been disappointed by an Oscar-winning movie and amazed by the one that didnít even get close? The same rule can be applied here. PageSpeed Insights tool is like the Academy of Motion Picture Arts: it evaluates the website in accordance with general criteria for the average websites. The scores are subjective and donít mirror the true experience a user has while loading your website. PageSpeed Insights results are not a rating of the actual speed of your website, but rather a rating based on a set of rules that Google believes are most relevant to page speed and performance.
Also, PageSpeed Insights tool doesnít take into consideration such important factor as caching. Properly done, it shortens the page load time, because such data as site logo, scripts and stylesheets has been cached, i.e. downloaded previously. It means, the first page view will take longer than a subsequent one, so a single page load time on its own doesnít reflect the average experience of your visitors.
Every developer knows that some background events and processes that are slow have nothing to do with the actual user experience. However, PageSpeed Insights tool evaluates those processes as well and includes the grades into the final website grade which is not correct either.
To back up our words with an example we inserted the URL of the Kenworth.com website into the PageSpeed Insights tool. The world-famous truck manufacturer with a seamless website user experience and a great amount of daily traffic. Letís see what grades it got:
Although the website is considered fast and the mobile and the desktop speed are less than 3 seconds, the scores are 66 and 21 for the mobile and desktop respectively. A little bit of a discrepancy, donít you think?
If your scores are lower than you thought theyíd be it doesnít mean that you should switch to another software provider immediately. PageSpeed Insights tool provides you with the guidelines which you could follow or not. Remember that web crawlers donít see your scores, they track how the visitors tend to behave while on your website. The website with low PSI scores can have high loading time and vise versa. Donít bother chasing those 100/100 grade, itís a waste of your time.
The site speed is important, but Google PageSpeed Insights canít provide you with the comprehensive grading, because this site doesnít take into account all of the factors which comprise seamless user experience. Google proves it itself. On the screenshot above you can see the following sentence: ďAlthough the page could be more optimized it is probably unnecessary.Ē So they acknowledge that those scores donít objectively grade the website speed and actual user experience and those recommendations they give are rather general, than specific.