In the pursuit of online dominance of your niche market, you may choose to add any number of tracking scripts to your website. You may even manage these scripts with a tag manager such as Google Tag Manager. The use of such scripts have the possibility of both great benefits and detriments.
The Benefits of Using Tracking Scripts
Tracking scripts, such as Google Analytics, Yandex, Hotjar, Bing Ads, Facebook Pixel, or Kiss Metrics — just to name a few — can help a business operator or marketing agency determine where customers are coming from, where they are going to, what they are clicking on, and where their attention is or is not focused on. Such information can be invaluable to determine viability of business initiatives such as money spent on pay-per-click or other advertisement, or whether visitors are flowing through your sales funnels or dropping off at a particular point.
By using Tag Managers, you can add, remove, or modify scripts that are being served for an entire site, through a web interface. Using a tag manager can save, the person responsible for managing the website, a considerable amount of time. In the age of GDPR (General Data Protection Regulations), you may be required to notify your visitors of your methods of collecting data, and this may also be done through logic embedded with a tag manager.
In short, you can learn an incredible amount of invaluable information from analytics and tracking services, and you can save a lot of time managing those scripts by using a tag manager.
What Happens In the Page
When you add any script to a web page that must run as soon as possible in order to do what it was designed to do, the script must be loaded, parsed, and then executed quickly. Analytic services are often very processor intensive as they are monitoring clicks, mouse moves, time on page, and a host of other actions.
However, every script that runs in your web page will cause the “First CPU Idle” time to be drawn out. This in turn will cause the “Time To Interactive” metric to be extended as well. If there is a tag manager involved, it may take additional time to inject the scripts into the page, which increases the “Speed Index” metric. All of these metrics contribute to your PageSpeed score. The higher the First CPU Idle, Time to Interactive, and Speed Index, the lower your PageSpeed score will be.
When It Affects Web Performance
Desktop devices, compared to mobile devices, have fast CPU processing, and fast connections to the internet. The impact by using one, two, or even five analytics scripts, for desktop browsers is, almost undetectable.
On mobile devices, however, each of these tracking or tag manager scripts can cost you anywhere from one to four PageSpeed points depending upon what else you have going on in your web page. If you are using Hotjar, Analytics, Facebook Pixel, and Bing Ads tracking, you could be experiencing a mobile web performance hit of up to 15 PageSpeed points.
But What If Your Visitors Are Mostly Using Desktop Devices
While you may not experience increased bounce rates (overall) if your visitors are predominantly desktop, we now live in a world of the Google mobile-first search index. According to reports from 2016, roughly 60% of Google’s global searches were performed on mobile devices. This is why in July of 2019, Google rolled out their mobile-first search index.
The mobile-first search index will grade your content and your speed based upon how mobile devices load and render your web pages. Tests show that there is a direct correlation to your PageSpeed score and your ranking. This means that if your website is slow on a mobile device, or that only shows thin content to a mobile visitor, the likelihood of you ranking better than a competitors site, which is fast and has rich content visible to mobile devices, is diminished.
As far as ranking in Google is concerned, you need to be focused first and foremost on how your site renders and loads for a mobile device.
In addition, a low PageSpeed score contributes to a low “quality” score when you are setting up pay-per-click in Google Ads. When you have a low quality score, your cost-per-click will go up.
If your site is one of those that was poorly constructed with a lot of bloat, you may already be struggling to attain a high mobile PageSpeed score. If you include heavy CPU intensive analytics scripts into your web pages, you could drag that score down even further. Remember, while a desktop PC may have a fast CPU, mobile CPUs are, relatively speaking, much slower.
Putting It Into Perspective And Making An Informed Decision
So, as a website operator, you have to make a choice. How much tracking information do you need? Do you need to have heat-maps? Do you need to have conversion tracking? Do you need to know when someone is leaving your sales funnels? Or can you get away with fewer tracking scripts?
You may answer that you need all of your analytic scripts. And that’s ok! Just understand that they will provide a performance hit, which may impact your probability to be found above your competitors in organic search and your quality score for your pay-per-click campaign.