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Everything you need to know about setting up Optimize including creating your account and container, linking to Google Analytics and how to tag your site.
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Page Speed Spike up when running experiment

Visitor ✭ ✭ ✭
# 1
Visitor ✭ ✭ ✭

Hi all,

 

I have been running experiments on one page for a month. 

I noticed that the page speed has been significantly slower than before. I have followed the instructions as mentioned and implement the hidden page tag on the top of the page and Optimize Script through GTM.

 

Do everyone else have the same problem? 

 

 

Screen Shot 2017-08-01 at 11.23.49 am.png

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Accepted by topic author kelly d
August 2017

Page Speed Spike up when running experiment

Google Employee
# 3
Google Employee

Hi Kelly

 

See the article at

https://support.google.com/360suite/optimize/answer/7359264?hl=en

 

Most performant option is to add GA and the Optimize plugin inline, on top of head, rather than deploying through GTM.

 

The reason is that unlikely typical GTM tags, Optimize needs to load and run before your page is shown to your users (in order to avoid flicker).

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Page Speed Spike up when running experiment

Follower ✭ ☆ ☆
# 2
Follower ✭ ☆ ☆

Hi, Kelly!
The page speed reports are heavily sampled in GA. It only counts 1% of the total traffic. I didn't have any problems due to implementing optimize. How is it implemented to your site?

What metric are you checking in GA?

Marked as Best Answer.
Solution
Accepted by topic author kelly d
August 2017

Page Speed Spike up when running experiment

Google Employee
# 3
Google Employee

Hi Kelly

 

See the article at

https://support.google.com/360suite/optimize/answer/7359264?hl=en

 

Most performant option is to add GA and the Optimize plugin inline, on top of head, rather than deploying through GTM.

 

The reason is that unlikely typical GTM tags, Optimize needs to load and run before your page is shown to your users (in order to avoid flicker).

Page Speed Spike up when running experiment

Visitor ✭ ✭ ✭
# 4
Visitor ✭ ✭ ✭

Hi Dimitris,

 

There is an option to deploy Optimize through GTM according to the instructions. I have prioritise tag firing and set the setup tag as Google Optimize to avoid delay.

 

So Best practice is to insert google optimize straight into the page code right?

 

Cheers,

Page Speed Spike up when running experiment

Google Employee
# 5
Google Employee

Hi Kelly,

 

Yes, while its very convenient to use GTM, as the article mentions this "will often result in significantly increased latency".

 

As I said, the reason is that while GTM and GA are typically non-essential to the function of a page (rendering a page is more important and these tags can run in the background a bit later), Optimize will change the appearance of your page and this has to happen before the page is shown to the user.

 

So to achieve best performance, you may need to move the analytics snippet and the Optimize plugin, on the very top of the head. This depends on the performance of your site: many sites are not very optimized (have a lot of external CSS or js), so using GTM will not have really a negative effect.

 

But if you have optimized your site and have carefully tuned performance (i.e. you have inlined CSS etc), then inserting analytics with the optimize plugin straight into the page, on the very top of the head, will be the best option.