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PageSpeed Insights "Speed" Metric

5:26 pm on Jan 12, 2018 (gmt 0)

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I was checking my website on PageSpeed Insights and I don't remember to have seen a "speed" metric before (that was a long time ago. Still, it shows "Unavailable" as a result.

They provide this link for that kind of result [developers.google.com...]
^^^^ https://developers.google.com/speed/docs/insights/faq#speedscoreunavailable

PageSpeed Insights
https://developers.google.com/speed/pagespeed/insights/ [developers.google.com]

[edited by: Robert_Charlton at 11:27 pm (utc) on Jan 12, 2018]
[edit reason] Added url with hashtag and removed specific domain from PageSpeed test [/edit]

10:42 am on Jan 13, 2018 (gmt 0)

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WebmasterWorld Administrator robert_charlton is a WebmasterWorld Top Contributor of All Time 10+ Year Member Top Contributors Of The Month

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Jonathan, thanks for linking to some of the key points. To elaborate a bit on what you posted...

Here's the PageSpeed test page, with a blank URL input field for members here to post their own urls. (For everybody's protection on WebmasterWorld, we don't publicly discuss test results on personal sites, so I removed the sample url posted.)

PageSpeed Insights
https://developers.google.com/speed/pagespeed/insights/ [developers.google.com]

As I read the additional documentation, "Speed" is obtained in PageSpeed Insights (PSI) by comparison with various datasets, browser info, etc.... and depending on the circumstances of your test (desktop, mobile, prototype, etc), the data may not be available directly. Thus, the "Unavailable" tab. In that case, Google has created other performance auditing tools to help you obtain useful performance indications and benchmarks in other ways.

This paragraph in the FAQ that was linked to in the OP is most relevant to that and leads to some important information. (On this forum, to preserve the hashtag as a named anchor, copy and paste it into your browser's address bar)....

Google PageSpeed Insights - FAQ - Speed Score Uavailable

Why am I not seeing any speed data for a URL?
PSI uses data from the Chrome User Experience Report [developers.google.com], which provides speed data for popular URLs that are known by Google's web crawlers. If the speed data for the queried URL is not available in the CrUX dataset, we recommend using Lighthouse [developers.google.com] to run a synthetic performance audit to estimate page speed, and investigate page optimization recommendations provided by PSI and Lighthouse.

I find the sources of data and the methodology particularly interesting, and, at my current stage of knowledge, challenging...
The Chrome User Experience Report is powered by real user measurement of key user experience metrics across the public web, aggregated from users who have opted-in to syncing their browsing history, have not set up a Sync passphrase, and have usage statistic reporting enabled....

Google's Lighthouse appears to be a major tool unto itself, compatible with a lot of building blocks that Google is providing.

Lighthouse is an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authentication. It has audits for performance, accessibility, progressive web apps, and more.

You can run Lighthouse in Chrome DevTools, from the command line, or as a Node module. You give Lighthouse a URL to audit, it runs a series of audits against the page, and then it generates a report on how well the page did....

https://developers.google.com/web/tools/lighthouse/ [developers.google.com]

I've thus far only gotten about 1/3 of the way through the 37-minute video introduction, which I strongly recommend as an introduction to the tool.

Extremely thorough, intended for both Progressive Web Apps and HTML web pages, so the performance of javascript that's clearly a part of most modern web pages* is part of the evaluation. There's no way to audit the performance of modern web pages simply by looking at the HTML source code.

*There's disagreement among some WebmasterWorld members about whether javascript belongs on web pages or should be avoided. I don't want to get into that in this discussion, but anyone who doesn't like javascript, please feel free to start another thread on this topic, which deserves some thorough examination.

I noticed in one of the test reports I ran with PSI that the tool identifies problems like rendering blocking CSS and javascript, in contrast to many earlier web page speed tools I've used which did not mention those. With regard to render blocking and page speed, see this thread from last year....

Is Critical Rendering Path the new Source-Ordered Content?
March 2017
https://www.webmasterworld.com/google/4841886.htm [webmasterworld.com]

Potentially much to be discussed.

11:03 am on Jan 13, 2018 (gmt 0)

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It looks like they have updated it. I have also lost a couple of extra points on the Mobile Optimisation score (from 92 to 90, see below). I too get Unavailable on the Speed score (but see e.g. [seroundtable.com ]).

I lose points (I get 97 on Desktop and 90 on Mobile) because of "render blocking resources". This is an informed choice: if you don't load external CSS first you just get that flash of unformatted page before the CSS loads. How this is improves User Experience escapes me. If "this page requires 1 additional round trips to load render blocking resources..." - the CSS - "...and 0.1 MB to fully render", I can live with it.

If I just want a better Optimisation score all I need to do is inline the CSS (I have tested this, and get scores of 100 on both Mobile and Desktop every time). Conversely, external CSS allows all formatting to be done in one place, and allows browsers to cache the file (so they only need an extra round trip on the first page load). Forcing the browser to load a couple of hundred lines of extra (duplicated) code on every new page load is not "best practice" in my view. However, cutting out a round trip might make more of a difference for users who are not in the same location as the server. Most of my target users (clients) are within 30 miles of the server, and almost none are in a different country. One round trip and 0.1 MB on the first page load is, to me, an acceptable cost.

The tool is probably helpful if you are new to web-design and employing a lot of Bad Practice generally, but is of limited value otherwise.
11:26 am on Jan 13, 2018 (gmt 0)

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@Wilburforce - agree 100% about the CSS.

Also everyone know that pages that use Google+ Api, Adsense, or anything else by Google, the test will fault you for no browser caching; not for your server config but for Google's. Seems they don't do what they tell everyone else to do.
1:19 pm on Jan 13, 2018 (gmt 0)

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votes: 2


This render blocking problem was supposed to be eliminated with http/2, was it not? I am using server push to serve the external css even before it is requested. But the pagespeed insight tool does not seem to utilize http/2 and push when it is complaining about render blocking css.

Still the result tells me that I probably do not need to do anything: "Data from the Chrome User Experience report indicates this page's median FCP (1.0s) and DCL (0.7s) ranks it in the fastest third of all pages. Although the page could be more optimized it is probably unnecessary. Learn more."
5:39 am on Jan 17, 2018 (gmt 0)

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WebmasterWorld Administrator robert_charlton is a WebmasterWorld Top Contributor of All Time 10+ Year Member Top Contributors Of The Month

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See this, recently posted thread, with overlapping information....

Page Speed Insights Use Data From Chrome User Experience Report
https://www.webmasterworld.com/google/4882877.htm [webmasterworld.com]