Website loading speed. All about the main metrics, ways to track data, and Google's June update

In June 2021, Google's functional search engine was supplemented with new ranking factors and site loading speed indicators in Lighthouse. From now on, to ensure the promotion of a site in Google , you need to understand the relevant metrics. Despite the fact that new technologies are being added, the Golden Web agency wants to get acquainted with the processes of site loading, its perception by users and tools to measure site loading speed.

Site optimization and user-centric metrics

The updated Lighthouse 6.0 algorithm is an automated tool for improving the quality of web pages and determining the speed of a site. It is an integral part of the work of a number of G o o g l e services, in particular, PageSpeed ​​​​Insights. User-Centric Performance Metrics, or metrics that focus on users, are individual Lighthouse 6.0 metrics with the potential to become a ranking factor in the near future. Their main difference is the focus on users' perception of the site's loading speed, rather than on the loading of the web resource itself.

User Experience and Loading Speed: Understanding the Difference

Until recently, the main metric for website loading was the load event – ​​the moment when a page, including its main resources, was fully loaded. While this is a powerful metric, it doesn’t provide users with information about the nature of the load.

Golden Web Agency will help you understand this by giving examples of two conditional sites "A" and "B". Both sites loaded at the same time, but the user will consider site "A" faster, because already during the loading he could see the relevant images and read the information. And in the case of site "B" - the user could only wait.

A similar situation will be observed with time to interaction. If, once the page has loaded, you still have to wait for the opportunity to scroll or click on a button, the user will most likely not like it.

◐ the speed at which the user gets a basic idea that the download has started;

◐ the speed at which a user sees small or large content on a page and can start exploring it;

◐ the amount of time the user waits to interact with the site;

◐ the presence of large element offsets to prevent the user from accidental or unexpected clicks.

As a result, Google has managed to form a number of metrics that it measures together with the load event for a comprehensive assessment of the behavior of the page during loading:

① TTFB . The so-called "time to first byte" reports the time it takes for the browser to receive the first byte of page content.

② FCB – “first full view.” This metric measures the time from the start of the load to the moment the user can see something.

③ LCP – “most complete display.” This is the length of time until the largest element on the page is fully displayed.

④ CLS – “template offset”, which defines the overall offset of objects on the page before and after they are loaded.

⑤ FID – “first input latency.” It measures the time that elapses between the user’s first action and the moment the browser is able to start processing that action.

⑥ TBT – “total blocking time”, during which so-called “long actions” (longer than 50ms) block the main flow and affect the usability of the page. This metric also measures what happens between FCP and TTI.

⑦ TTI – “time to full interactivity”.

⑧ Speed ​​Index – “site speed index” and visual display of content during screen loading.

Additionally, there are also three metrics LCP, FID CLS, which are combined into the Core Web Vitals group and used in ranking. However, the site loading speed needs to be analyzed as a whole, and not just optimized for Web Vitals metrics - Golden Web agency explains why below.

Search engine optimization involves finding the best way to check the speed of your website. One of the easiest ways to do this, at first glance, is to use the PageSpeed ​​Insights and LightHouse reports. But high scores do not guarantee that your website will load quickly, and low scores do not mean that your website is slow. It is worth noting that Google does not take into account scores in its reports, but measures data from real users.

➜ Imagine a site with a gaming theme for old PCs that has a high loading speed of the mobile version. It is logical that the site will receive a higher percentage of users with old versions of browsers on PCs. However, although there are excellent pagespeed indicators of the mobile version, some users will not have a very high loading speed of the site. As a result, it will have poor performance for G o o g l e .

➜ Now let's analyze the opposite situation - a website with low pagespeed indicators and a poor mobile version. This could be a SAAS service used mainly by PC users. By getting a good interaction experience, the site will get good indicators in G o o g l e .

Both examples demonstrate the fundamental difference between theoretical and practical Lab and Field data.

Lab Data is laboratory data obtained from a one-time test of a specific URL and generated by Gtmetrix, Lighthouse and PageSpeed ​​Insights, without which it is difficult to promote a site. Site optimization is carried out more effectively thanks to such services, because they:

● provide the ability to track individual URLs;

● is a tool for measuring metrics on test websites and the level of their optimization by developers;

● provide tips for improvement.

At the same time, optimizing a site for search engines using these services has its own disadvantages:

● inability to use for tracking individual types of pages (pagegroups) and detailed statistics of the entire website;

● provide almost no information about real users, except for observation data;

● hints may not affect metrics, some of which can only be measured in TBT, TTI, or Speed ​​Index.

Another type of data to consider when optimizing your site is Field Data, which shows real-world metrics and user data. However, it only provides monthly figures, updated every second Tuesday of the month, and does not allow you to track data for analysis of individual URLs or pagegroups. An example of Field Data is the Chrome UX report, which contains website data from the Google Chrome browser .

Successful SEO promotion involves analyzing Web Vitals events, which are used by the browser API and send data to another source, such as Google Analytics ( GA ). Such a report can:

◐ be used to analyze individual URLs, pagegroups, or the entire site;

◐ show data for any period (e.g. month, week or day);

◐ act as a source for creating reports by date or device;

◐ segment and analyze users (events) with poor or good performance.

However, it is not easy to carry out high-quality website promotion using Web Vitals events, because this type of data:

● requires developer intervention to implement events on the site or via Google Tag Manager;

● sends a large number of events to GA;

● the data provided is by default not very informative for an individual user, it only has an average value and GA ID;

● requires changing event tags when creating dashboards.

Thus, each of the three methods of measuring data has its own advantages and disadvantages. That is why the Golden Web agency recommends using data from different sources for SEO promotion of the site in G o o g l e :

► Lab – when developing and measuring changes;

► Field - for tracking real data;

► Web Vitals – for tracking data by device, date, and region in large projects with active development.

At the same time , it is important to focus on users rather than service metrics when developing tasks. This is exactly the approach that Google follows , developing user-centric metrics. We can summarize:

① Lighthouse metrics will become one of the main ranking factors for Google search engine from June 2021.

② They focus on both the loading speed of the site and its user perception.

③ The correct combination of laboratory (theoretical) and field (for a specific user who decided to visit the site from a specific device) methods of collecting data on metrics will allow you to achieve the most effective site promotion.

④ Golden Web Agency recommends using user-centric metrics similar to Google – only then will you be able to get the best results from website SEO promotion!