CVS offers an attractive carousel of rotating images on its m-commerce site home page. Dropping just one of the promotional images reduced page load time from 13.67 seconds to 9.67 seconds, according to the Keynote Mobile Commerce Performance Index.

It’s possible CVS Caremark Corp. gave its mobile shoppers too much of a good thing.

On its mobile commerce web site home page, CVS features an attractive carousel of rotating images that often showcase special promotions. Such was the case for the week ending July 27, when it included in the carousel, among other things, a banner promoting 20% off all online purchases with a coupon code. That week, the m-commerce site home page loaded on average in 13.67 seconds, according to the Internet Retailer-exclusive Keynote Mobile Commerce Performance Index.

However, for the week ending August 3, CVS removed that promotional banner from the carousel rotation and its mobile home page loaded on average in 9.67 seconds, a 29% drop, the index finds. Mobile and web performance management firm Keynote recommends a maximum page load time of 4.5 seconds on a blend of 3G and 4G networks, which is how the index measures mobile sites. The average mobile page load time for all 30 retailers on the index for the week ending August 3 is 12.00 seconds.

A 1-second delay in web site page load time translates into a 7% loss in conversions, according to I.T. research firm Aberdeen Group. So if an e-retailer makes $100,000 a day online and on mobile, a 1-second page delay could mean around $2.5 million in lost sales every year.

So, the question becomes, did the sitewide 20%-off promotion generate enough in mobile sales to offset sales lost to the extra 4 seconds it took for the m-commerce site home page to load? CVS did not respond to a request for comment.


CVS uses Data URI encoding techniques for image optimization of site resources, including icons and navigation arrows, says Venkatesh Giri, mobile performance expert at Keynote. Data URI is a scheme of encoding data within a web page that make up page elements, such as images or CSS, a mark-up language used to define pages and denote where elements appear on a page. With multiple elements encoded within a page, no extra HTTP server request is made to fetch each of the embedded elements. URI stands for universal resource identifier, a string of characters used to identify a web resource, such as an image.

“However, CVS does not employ the same optimization to banner or promotional images served up by its content delivery network,” Giri says. “CVS can further improve its page load time by using image-optimization techniques for its image carousels. We’ve seen this before, where big promotions have a substantial effect on load times, especially in the mobile environment. Retailers really need to pay attention to the best performance-optimization techniques when running promotions to minimize the impact on home page load times.”

CVS was No. 11 on the Keynote index for the week ending August 3. Sears Holdings Corp topped the index with a load time of 2.23 seconds, a success rate of 99.71%, and a score of 993 out of 1,000. (Keynote equally weights and combines load time and success rate to achieve a score). The Sears m-commerce site home page contains six page elements that together weigh 49 kilobytes.

To see complete results (including response time, site availability, page weight in kilobytes, total page elements, and index score) for all 30 retailers on the Keynote Mobile Commerce Performance Index, click here.


Keynote measures, exclusively for Internet Retailer, 28 stand-alone m-commerce sites optimized for smartphones and two responsive design sites, which are single sites that render content in ways that fit the screen size of a device, including desktop PCs, tablets, smartphones and smart TVs. For the index, Keynote measures the smartphone versions of the responsive sites.

The 30 representative sites include merchants in multiple categories and channels, and of multiple sizes, ranging from such giants as Inc. to mid-sized retailers like LLC. Keynote tests the sites in the index every hour Monday through Sunday from 8:00 a.m. through midnight EDT, emulating the Apple iPhone 5 smartphone on two wireless networks: AT&T and Sprint, both using 3G, 4G and 4G LTE networks. Keynote runs the tests in Dallas, New York and San Francisco.

Keynote combines a site’s load time and success rate, equally weighted, into a single score. Given that both performance and availability are important, the score reflects the overall quality of the home page; a higher score indicates better performance. Scores also reflect how close sites are to each other in overall quality. The index average score is the midpoint among all the sites’ scores. To consistently rank high on the Keynote index, sites must hit availability targets of 99.5% or better and be faster than 10 seconds to load on average. Top-performing sites load in under five seconds.

Today, 20% of U.S. Internet-enabled mobile phone users have 4G or 4G LTE wireless data connections, 71% have 3G, and 9% have 2G, according to research firm Informa Telecoms & Media. And according to research and consulting firm Deloitte, 63% of U.S. smartphone users most often connect to the web on their devices on a Wi-Fi network.