Web Performance Optimization and Google Tag Manager

July 31, 2018
Pam

Web Performance Optimization and Google Tag Manager

Big Data is the next big thing. You probably hear that a lot lately. And it’s quite obvious that your Big Data strategy requires data, and data requires tags. But, do your tags slow down your page load times? On this post, we’ll talk about how Google Tag Manager affects page rendering.

Why are faster websites better?

Developing a fast website will allow your company to obtain:

  • better conversion rates
  • increase of pageviews
  • increase of filled forms
  • better search engine rankings
  • lower server bandwidth costs
  • lower website abandonment rates
  • happiest customer
  • customer loyalty

A few seconds of load time could push your customers to a competitor, don’t let this happen!

What about Analytics?

To build a fast and user-friendly experience, you should use a Tag Management system like Google Tag Manager. If you are currently using a tag management system, you should review your tag management system at least annually to remove 3rd-party tags that are no longer in use.

What is Google Tag Manager (GTM)?

“Google Tag Manager is an asynchronous tag, meaning that when it executes, it does not block other elements from rendering on the page. It also causes the other tags that are deployed via Google Tag Manager to be deployed asynchronously, meaning that a slow loading tag won’t block other tracking tags.”

GTM optimizes web performance by reducing the number of calls to external resources when your pages load. Tag Manager utilizes something called the Data Layer to store information about the users session. To read a complete explanation, read this excellent post on the Data Layer.

A simple example to illustrate how the Data Layer works is with an e-commerce website. The Data Layer captures the e-commerce transaction number, value, SKU, and other important information. This data is stored in a place that other programs like Google Analytics, third-party software, and more can access and pull data from.

Here is an even simpler explanation, we are based in Las Vegas where buffets are never too far away. Think of the Data Layer like a two-sided buffet table, two people can access the food tray to grab what they need. Without it, each person would have to go to the food server, place their order, and wait.

This is the magic of Tag Manager, the data is stored in this “buffet table” and external programs can grab the information they need without multiple server requests.

What is the best metric for measuring website speed?

Now, we see that Tag Manager can save speed, we can measure and improve website performance and see which of your optimizations work best?

We recommend using the Navigation Timing API, which is now supported across many of the modern desktop and mobile browsers.

Then, you can gather this data and send it back to Google Analytics for further analysis, and could be used for generating useful reports of a real user on desktop and mobile from a wide variety of different network.

Here is a performance.timing object in Google Chrome

But, what are the best metrics to measure? We recommend taking the metrics that correspond to page usability. The browser paints the page when the render tree is constructed, which means, the DOM and CSSOM are loaded. As a best practice, you should be listening for domContentLoadedEventEnd, it is when the DOM ready event is fired.

To conclude, every company should care about how their website performs because a faster website is not only a top ranking factor for Google and other search engines, but it is also a known influencer in conversion rates.

Summary:

You should pay attention to the structure of your website, eliminate the number of critical resources on the page, and optimize the critical path length. 

Then, deploy tags asynchronously via Google Tag Manager and make an appropriate conversion tracking implementation with dataLayer object.

Prioritize, monitor and clean you third-party tags throughout the course of the data life-cycle in order to avoid slowdowns, as well as improve your data quality and collection.

Moreover, making a successful website require speed insight. Analytics should be your best friend and not a thread for website performance optimization.

Use a rational metric for measuring website speed and use both analytics and monitoring tools like Google Page Insights. You may discover that your website loads better on some browsers, devices or in specific geographic areas. With these insights, you can begin to improve your site performance in a targeted way. There are always places for page speed improvement.