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>Cumulative layout shift is supposed to measure whether your site shifts around while it's loading, but it's so strict that even Google Translate fails the test

>Cumulative layout shift is supposed to measure whether your site shifts around while it's loading, but it's so strict that even Google Translate fails the test. And so it should be. There's hardly anything worse than having things shift around after you start reading, scrolling or clicking on something. I think it's a very good sign if Google's own sites fail these tests. It means the tests are meaningful.

rsynnott 5y ago
On the other hand, it means that Google has stopped caring about UI performance. Of course, anyone who’s used Google Groups lately could tell you that.
- trasz 5y ago
  Priority is the ads display performance; search or news are just an addition to the actual business.
- sim_card_map 5y ago
  or Gmail for the last 10 years
- refulgentis 5y ago
  I'm not sure its reasonable to jump from "Google Translate has a jump' to "Google has stopped caring about UI performance"
  - rsynnott 5y ago
    As I say, compare Google Groups today to Google Groups 10 years ago. Or gmail. Or Calendar. Though Groups is possibly the best example, as it went, more or less overnight, from one of Google's snappiest properties to about its most sluggish. Google used to be very concerned about UI performance, but they seem to have totally lost interest in it.
- Tempest1981 5y ago
  My theory is that they test this on their 10 Gbit company network, and high-end laptops, and it works great. So it's hard to convince anyone that it's a problem.
  - lrem 5y ago
    In the office we are strongly encouraged to try our stuff with the WiFi network degraded to perform like EDGE (apparently nobody cares about GPRS any more). Obviously that hasn't been exercised much since last spring.
  - tdaltonc 5y ago
    Most Google offices have multiple wifi networks for simulating different kinds of degraded connectivity.
zelphirkalt 5y ago
I feel like there should be additional constraints. For example a page that looks so simple like the google search page should have a limit on how much code it needs to get there. Basically a bloat alarm, lighting up in red, once bloat is detected. And it would be redder than red for Google itself and things like YouTube.
adkadskhj 5y ago
> And so it should be. There's hardly anything worse than having things shift around after you start reading, scrolling or clicking on something. Oh my god, this is one of my largest complaints. I'm an impatient person so i often go to click something before the page is done - bad me - and so often JS loads and swaps buttons. Honestly though i've had that complaint about my OS', too. The number of times i'm typing and something pops up and steals focus or i go to click something and moments before it shifts causing me to click something else.. ugh.
- reaperducer 5y ago
  When I switched to Mac, that was one of the most refreshing things about OSX: apps weren't allowed to steal focus. Sadly, that's no longer true.
  - ancarda 5y ago
    Is that a very recent change? I don't know that I've ever noticed that on macOS, but I started using this OS around Lion, I think
- kmeisthax 5y ago
  If I was a native widget toolkit designer or web developer I'd implement a rule that all layout changes must be rendered and on the screen 150ms before input handling can use them. Lag compensation for local user input. If you click a button at the same time it moves, you should still click what was on the screen at the time you pressed the button. Yes, I know this effectively means having to keep two copies of the widget tree (one for input and one for output) and applying all changes as diffs. Don't care. I'll buy more RAM.
- seanp2k2 5y ago
  I know something worse: websites that force you to use their app, providing links that don’t actually take you to that content in the app. Two examples with the same experience: Instagram and Reddit. They block functionality on the mobile web pages in Safari, pop up large buttons to get you to use the app, then those buttons take you to the iOS App Store page even though I already have each installed, then clicking “open” there just opens each app to the default home page, NOT the content I was trying to access but was subsequently blocked from accessing. Result: I decide that I don’t care about that content anyway and just go do something else. Trying to log in via mobile site, forgetting my password, going through the reset flow, logging in again because my pw reset session happened in GMail’s safari context session and didn’t save cookies to main safari, all while being hounded constantly that “it’s better in the APP!”…just keep it. Pinterest is uniquely bad because the thing you see the photo of doesn’t actually take you to the place where that came from. Add in all the ads, the page wasting tons of space with spacing / white space / low density, the placement on Google for so many thing, and I cringe whenever I see a Pinterest result. Quora isn’t much better. Amazon and eBay at least take you to the right place with their “open in app” bars at the top of the page. Not an iOS dev but I’m assuming they’re using some special Safari APIs to do that instead of useless generic App Store links that don’t pass through context. I really wish Google / Apple would punish sites for doing this, since it leads to such a bad UX. Please think about that, marketing and product people: I literally already have your apps, but you’ve made the mobile web page so annoying in trying to get me to use the app, that any interesting content I do find via SERP I discard instantly as inaccessible due to the hassle of trying to search for that same content through your apps, because you’ve intentionally broken the mobile web experience.
tyingq 5y ago
"I think it's a very good sign if Google's own sites fail these tests. It means the tests are meaningful." I agree, that appears to be a good sign. I am curious to what degree Google will reward fast sites and punish slow ones. I wonder if they are willing to make big shifts in the rankings.
Alex3917 5y ago
> There's hardly anything worse than having things shift around after you start reading, scrolling or clicking on something. Most sites that fail for CLS don't have any CLS that's visible to the user.
cecilpl2 5y ago
Google Search fails the cumulative layout shift test. I can't count the number of times the "People also search for" box pops up in the middle of my search results 3-4 seconds after load. It's just enough time for me to identify the result I want, move the mouse there, and then proceed click on the new, different link that just loaded under my mouse. It's infuriating.
- diveanon 5y ago
  At this point you have to assume that is by design.
  - tomcooks 5y ago
    I don't understand the downvotes you are getting, considering how they used such tricks whenever possible
  - rightbyte 5y ago
    Ye. It is like those adds in Android apps that happen to load where the button you try to click was. It is obvious someone at Google is trying to game some metric with accidental clicks.
  - maccard 5y ago
    It's more likely the people who develop and test and prioritize the features live in mountain view, with 5g and gigabit fiber with ultra low latency to the data centers.
    - prollings 5y ago
      Sure, but these people must have left that golden zone at some point and had their clicks stolen like the rest of us.
    - dylan604 5y ago
      That's why the dev tools in browsers have an option to simulate slower data speeds to test this kind of thing. Having good connectivity and failing to provide a useable experience for slower connections is just bad dev work.
aparsons 5y ago
YouTube does this notorious thing where the ad above the first search result appears after the results, so you accidentally click the ad.
- pclmulqdq 5y ago
  It's almost as if they get paid per click on that ad... There's no incentive for them to fix this, unfortunately. Everywhere else on YT there's a nice gray box that keeps the place of a UI element until that element loads.
hateful 5y ago
At my second job around 2004 my boss was very strict about not having the page move on load, it was a big deal. But over the years, especially recently, I've noticed so many sites and apps that shift constantly and it seems that it's not a priority anymore. Just yesterday, opening the Amazon app, and the "Orders" button shifted before I could click it!
- bryanrasmussen 5y ago
  is your old boss still around - how is his site?
- epistasis 5y ago
  Web development has gone a long ways backwards over the years. The tech is so complicated that developers focus on their own productivity over basic user experience. It feels like it's been a long long long time since I've even seen a web article focus on good UI, instead it's all about how to handle all the layers of complexity or new tooling.
swiley 5y ago
Google's pages are some of the worst for this. It's not hard to build pages without these problems but everyone is way too caught up in fancy web design they ignore UX.
dazc 5y ago
I don't think anyone would disagree but, as things stand, you can have a page where things DO NOT visibly 'shift around' but still fail the test. I feel sorry for all the developers who are going to be inundated with complaints because their client's sites have failed yet another perceived important benchmark.
- epistasis 5y ago
  Visible to whom? Web developers often have no clue how their page appears to others, because they are developing locally, and the production site is close and has few network issues. So a lot of developers that think everything is fine end up having no clue what most people experience. When web fonts first started seeing widespread use, I would very frequently see 2-10 second delays when all content had loaded except for the font, including massive images, but I couldn't see any text. When I complained about this trend in the web to web developers I knew, almost none of them even seemed to believe it was possible, or at worst I was just a very unlucky user.
  - dazc 5y ago
    It should be obvious to a developer that he/she should test outside of this closed enviroment but, I agree that it's possible many do not. I stand by the statement that you can still fail the test despite having content that does not 'visibly' shift though.
    - fauigerzigerk 5y ago
      So what would cause this kind of shift?
foobiter 5y ago
do you think they penalize themselves for it?
atkbrah 5y ago
I think sometimes windows settings (the modern settings application) fails at this too.
daed 5y ago
Gmail shifts almost every time I click on the Promotions tab. I go to click my top unread email and instead end up clicking an ad.

rsynnott 5y ago

On the other hand, it means that Google has stopped caring about UI performance. Of course, anyone who’s used Google Groups lately could tell you that.

trasz 5y ago
Priority is the ads display performance; search or news are just an addition to the actual business.
sim_card_map 5y ago
or Gmail for the last 10 years
refulgentis 5y ago
I'm not sure its reasonable to jump from "Google Translate has a jump' to "Google has stopped caring about UI performance"
- rsynnott 5y ago
  As I say, compare Google Groups today to Google Groups 10 years ago. Or gmail. Or Calendar. Though Groups is possibly the best example, as it went, more or less overnight, from one of Google's snappiest properties to about its most sluggish. Google used to be very concerned about UI performance, but they seem to have totally lost interest in it.
Tempest1981 5y ago
My theory is that they test this on their 10 Gbit company network, and high-end laptops, and it works great. So it's hard to convince anyone that it's a problem.
- lrem 5y ago
  In the office we are strongly encouraged to try our stuff with the WiFi network degraded to perform like EDGE (apparently nobody cares about GPRS any more). Obviously that hasn't been exercised much since last spring.
- tdaltonc 5y ago
  Most Google offices have multiple wifi networks for simulating different kinds of degraded connectivity.

zelphirkalt 5y ago

I feel like there should be additional constraints. For example a page that looks so simple like the google search page should have a limit on how much code it needs to get there. Basically a bloat alarm, lighting up in red, once bloat is detected. And it would be redder than red for Google itself and things like YouTube.

adkadskhj 5y ago

> And so it should be. There's hardly anything worse than having things shift around after you start reading, scrolling or clicking on something. Oh my god, this is one of my largest complaints. I'm an impatient person so i often go to click something before the page is done - bad me - and so often JS loads and swaps buttons. Honestly though i've had that complaint about my OS', too. The number of times i'm typing and something pops up and steals focus or i go to click something and moments before it shifts causing me to click something else.. ugh.

reaperducer 5y ago
When I switched to Mac, that was one of the most refreshing things about OSX: apps weren't allowed to steal focus. Sadly, that's no longer true.
- ancarda 5y ago
  Is that a very recent change? I don't know that I've ever noticed that on macOS, but I started using this OS around Lion, I think
kmeisthax 5y ago
If I was a native widget toolkit designer or web developer I'd implement a rule that all layout changes must be rendered and on the screen 150ms before input handling can use them. Lag compensation for local user input. If you click a button at the same time it moves, you should still click what was on the screen at the time you pressed the button. Yes, I know this effectively means having to keep two copies of the widget tree (one for input and one for output) and applying all changes as diffs. Don't care. I'll buy more RAM.
seanp2k2 5y ago
I know something worse: websites that force you to use their app, providing links that don’t actually take you to that content in the app. Two examples with the same experience: Instagram and Reddit. They block functionality on the mobile web pages in Safari, pop up large buttons to get you to use the app, then those buttons take you to the iOS App Store page even though I already have each installed, then clicking “open” there just opens each app to the default home page, NOT the content I was trying to access but was subsequently blocked from accessing. Result: I decide that I don’t care about that content anyway and just go do something else. Trying to log in via mobile site, forgetting my password, going through the reset flow, logging in again because my pw reset session happened in GMail’s safari context session and didn’t save cookies to main safari, all while being hounded constantly that “it’s better in the APP!”…just keep it. Pinterest is uniquely bad because the thing you see the photo of doesn’t actually take you to the place where that came from. Add in all the ads, the page wasting tons of space with spacing / white space / low density, the placement on Google for so many thing, and I cringe whenever I see a Pinterest result. Quora isn’t much better. Amazon and eBay at least take you to the right place with their “open in app” bars at the top of the page. Not an iOS dev but I’m assuming they’re using some special Safari APIs to do that instead of useless generic App Store links that don’t pass through context. I really wish Google / Apple would punish sites for doing this, since it leads to such a bad UX. Please think about that, marketing and product people: I literally already have your apps, but you’ve made the mobile web page so annoying in trying to get me to use the app, that any interesting content I do find via SERP I discard instantly as inaccessible due to the hassle of trying to search for that same content through your apps, because you’ve intentionally broken the mobile web experience.

tyingq 5y ago

"I think it's a very good sign if Google's own sites fail these tests. It means the tests are meaningful." I agree, that appears to be a good sign. I am curious to what degree Google will reward fast sites and punish slow ones. I wonder if they are willing to make big shifts in the rankings.

Alex3917 5y ago

> There's hardly anything worse than having things shift around after you start reading, scrolling or clicking on something. Most sites that fail for CLS don't have any CLS that's visible to the user.

cecilpl2 5y ago

Google Search fails the cumulative layout shift test. I can't count the number of times the "People also search for" box pops up in the middle of my search results 3-4 seconds after load. It's just enough time for me to identify the result I want, move the mouse there, and then proceed click on the new, different link that just loaded under my mouse. It's infuriating.

diveanon 5y ago
At this point you have to assume that is by design.
- tomcooks 5y ago
  I don't understand the downvotes you are getting, considering how they used such tricks whenever possible
- rightbyte 5y ago
  Ye. It is like those adds in Android apps that happen to load where the button you try to click was. It is obvious someone at Google is trying to game some metric with accidental clicks.
- maccard 5y ago
  It's more likely the people who develop and test and prioritize the features live in mountain view, with 5g and gigabit fiber with ultra low latency to the data centers.
  - prollings 5y ago
    Sure, but these people must have left that golden zone at some point and had their clicks stolen like the rest of us.
  - dylan604 5y ago
    That's why the dev tools in browsers have an option to simulate slower data speeds to test this kind of thing. Having good connectivity and failing to provide a useable experience for slower connections is just bad dev work.

aparsons 5y ago

YouTube does this notorious thing where the ad above the first search result appears after the results, so you accidentally click the ad.

pclmulqdq 5y ago
It's almost as if they get paid per click on that ad... There's no incentive for them to fix this, unfortunately. Everywhere else on YT there's a nice gray box that keeps the place of a UI element until that element loads.

hateful 5y ago

At my second job around 2004 my boss was very strict about not having the page move on load, it was a big deal. But over the years, especially recently, I've noticed so many sites and apps that shift constantly and it seems that it's not a priority anymore. Just yesterday, opening the Amazon app, and the "Orders" button shifted before I could click it!

bryanrasmussen 5y ago
is your old boss still around - how is his site?
epistasis 5y ago
Web development has gone a long ways backwards over the years. The tech is so complicated that developers focus on their own productivity over basic user experience. It feels like it's been a long long long time since I've even seen a web article focus on good UI, instead it's all about how to handle all the layers of complexity or new tooling.

swiley 5y ago

Google's pages are some of the worst for this. It's not hard to build pages without these problems but everyone is way too caught up in fancy web design they ignore UX.

dazc 5y ago

I don't think anyone would disagree but, as things stand, you can have a page where things DO NOT visibly 'shift around' but still fail the test. I feel sorry for all the developers who are going to be inundated with complaints because their client's sites have failed yet another perceived important benchmark.

epistasis 5y ago
Visible to whom? Web developers often have no clue how their page appears to others, because they are developing locally, and the production site is close and has few network issues. So a lot of developers that think everything is fine end up having no clue what most people experience. When web fonts first started seeing widespread use, I would very frequently see 2-10 second delays when all content had loaded except for the font, including massive images, but I couldn't see any text. When I complained about this trend in the web to web developers I knew, almost none of them even seemed to believe it was possible, or at worst I was just a very unlucky user.
- dazc 5y ago
  It should be obvious to a developer that he/she should test outside of this closed enviroment but, I agree that it's possible many do not. I stand by the statement that you can still fail the test despite having content that does not 'visibly' shift though.
  - fauigerzigerk 5y ago
    So what would cause this kind of shift?

foobiter 5y ago

do you think they penalize themselves for it?

atkbrah 5y ago

I think sometimes windows settings (the modern settings application) fails at this too.

daed 5y ago

Gmail shifts almost every time I click on the Promotions tab. I go to click my top unread email and instead end up clicking an ad.