American Airlines Inc. took a nose dive this week, falling 11 spots on the AppDynamics/Mobile Strategies 360 Performance Index 3G index for the week ending March 6. The index monitors the site speed and general performance of 30 mobile sites.

American Airlines dropped to No. 14 from No. 3 the previous month because of a 2.0-second increase in the time it took for the web browser to start drawing the visual elements on the mobile home page, known as the start render time, says Peter Kacandes, senior product marketing manager, mobile, web and synthetics, for AppDynamics. The time for the homepage to finish drawing the mobile elements on the page—the visually complete time—also increased by 2.3 seconds, which also contributed to the drop in index ranking, he says. American Airlines did not respond to a request for comment.

Heading in the other direction, flash sale e-retailer Inc., formerly NoMoreRack, jumped up to No. 5 from No. 14 on the 3G index. Choxi’s visually complete time decreased 1.7 seconds and its start render time decreased 0.9 seconds, Kacandes says.

“Choxi moved up nine places despite a two-megabyte increase in complete load and a significant increase in resources loaded from 225 to 371,” Kacandes says. Complete load is home page weight; Resources include the elements that make up a page, such as images and buttons.

On the 4G index, mobile sites and were the biggest movers for the week ending March 6. climbed seven spots to clinch the No. 1 position, after it reduced its visually complete time by almost two seconds. also jumped 11 spots to the No.  7 position.


The exclusive AppDynamics/Mobile Strategies 360 Index tracks key mobile site metrics across a range of sites to calculate a weekly average Speed Score on both 3G and 4G mobile carrier networks. The index represents a snapshot of mobile site performance across industries, including retailers such as, insurance companies such as and restaurants such as

AppDynamics each week measures performance metrics of both 3G and 4G networks for each of the 30 sites in the index to determine each site’s Speed Score.

They include:


First render: The time, (in seconds) it takes until the web browser starts drawing the visual elements of a home page.

Visually complete: The time (in seconds) it takes until the web browser has completed drawing the visual elements of a home page.

Number of elements loaded: The number of resources loaded by a home page.

Complete load: The size of the home page when all data is loaded (in megabytes).


Using these metrics, the index calculates the Speed Score. The Speed Score is a ratio that rewards businesses for displaying more visual content on the mobile home page earlier rather than later. The earlier a mobile site home page looks complete to a consumer, the better the mobile experience for the visitor, even if a few remaining elements are displayed later. A site with a higher ratio of content displayed earlier will have a better Speed Score than a site with the same visually complete time but a longer first render time.

For example, site A may have a visually complete home page load time of three seconds, loading 90% of its content in the first second and the remaining 10% in seconds two and three. Site B may have the same three-second visually complete time, but present zero content in the first two seconds and 100% in the third second. The sites have identical visually complete times, but Site A will be perceived as much faster, and will earn a better Speed Score as a result.

The index displays the average across the 30 mobile sites for each metric as well as the average Speed Score on both 3G and 4G networks for each mobile site.

For the week ended March 6, the average Speed Score for 3G was 9.8 seconds the same as the previous month. The average first render was 6.8 seconds compared to 6.6 seconds the previous month.


Visually complete average was 15.4 seconds the same as the previous month. Average number of elements loaded was 100.2 compared with 96.0 the previous month. Average home page weight was 1.6 megabytes compared with 1.8 megabytes the previous month.

On 4G, the average Speed Score was 5.7 seconds compared with 6.4 seconds the previous month. The average first render was 4.0 seconds compared with 4.2 seconds the previous month.

Visually complete average time was 8.7 seconds compared with 9.7 seconds the previous month. Average number of elements loaded was 100.2 versus 96.2 a month earlier. And average home page weight was 1.7 megabytes compared with 2.0 megabytes the previous month.

The index is accompanied by a chart on that is refreshed weekly to illustrate how each mobile site performs as well as index averages. Click here to access the performance chart for the week ending March 6.



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