By Jeffrey Vocell, Product Marketing Manager, SiteSpect
There are a number of studies available from companies, as well as independent research firms, that show how site speed affects key business metrics. For example, Amazon found that just every 0.1 seconds (100 milliseconds) of delay translates to 1 percent of lost sales. Google found that a mere 0.5 seconds (500 milliseconds) of delay resulted in 20 percent loss in traffic. So its no surprise that you would want pages to load quickly, right?
“Adding JS has an inherent performance cost and performance risk. Think about the ROI. If it’s not useful for your business goals, don’t keep it on your site just because it’s popular or nice looking.” – Yottaa
If you conduct a test and page speed is different between your tested version of the page and a new version of the page (even if it’s only 0.1 seconds), user behavior can be affected and test results should be questioned due to the speed implications. Ensure that you are closely monitoring site speed alongside test results to ensure that slower pages are not skewing results.
Tested content could change suddenly
Flicker effect is a common occurrence as a result of testing images. We have all likely seen it and the effect occurs when part of your page is loaded in the visitor’s browser and then overwritten with different content. This could mean that an initial hero image is loaded featuring a child wearing a raincoat and carrying an umbrella, but then another image writes over it showing something different. Images are not the only type of content that has the potential to flicker. Flicker could also be seen in button color, video, or any other on-page element. These types of tag-based artifacts can be disorienting to end users, and introduce noise into test data that can ultimately lead you to make bad decisions.
Flicker effect is noticeable especially if you visit a page that is knowingly being tested, then clear your web browser cookies and refresh that same page in your browser. For example, take a look at these two videos that clearly show flicker effect:
1. In this first example, we see two elements of the page flicker. First the left-hand column text flickers between 5-7 seconds, as it clearly disappears and then comes back. Even more pronounced in this video, though, is the main image which begins to change about 7 seconds into the video and then loads a brand new image.
2. In the second example, we see some text that flickers, and as a result shifts some of the other on-page elements. Watch the text above the blue button at the 13-second mark and you will see this change as well as the button moving. Think about this in terms of you visiting a page, if you were 13-14 seconds into a page visit and something suddenly changed, what would you think?
Tested images load twice, slowing down site speed
For this post, we looked at five popular online retailers and looked at the file size of their main images:
If we assume that each of these images is being tested, then the browser is loading up to double the file sizes that are listed. So if it takes 0.5 seconds to load, then with testing (due to double-loading) we can estimate that it will take this process a full second to complete. Given the business implications we shared in the first point – that single extra second from just loading one image can have a huge impact on how users interact with your website and bottom-line business results.
Potential for interrupting portions of your site
Not only could this turn away potential visitors thinking that they may be experiencing technical issues with your site, but it could mean lost revenue and referral traffic as well.
Requires attention from your IT resources
Your IT team is busy keeping all of the technology, devices and people that interact with them in perfect harmony on a day-in and day-out basis. So working with them in the best and most efficient way is crucial to success for your marketing technology objectives. But by constantly adding tasks and requests to their backlog for adding tags to your site, you are effectively taking time that they could be focused on other enhancements or technology objectives.
Some tag-dependent vendors require a new tag for each element on the page being tested – this has two main effects on your team:
1. It takes away central knowledge of testing and building a culture of optimization from your team, as you are always dependent on your IT group.
2. It takes away your ability to be agile and implement tests quickly due to lengthy deployment schedules.
In conclusion, be aware of the effects that tags are having on your website and testing performance. Quantify the impacts of these hidden drawbacks and determine if they affect on your bottom line. Even tag-dependent vendors agree that the less content-rendering tags you have on your site, the better you are, so talk to your team and eliminate any unneeded tags from pages.
About the Author
Jeffrey Vocell is the Product Marketing Manager for SiteSpect, where he’s responsible for strategy and communication of product messaging. Prior to SiteSpect, Vocell co-founded Trendslide, a mobile business analytics startup. He holds a B.S. in Business Management and Leadership from Daniel Webster College.