As end users become more discerning in the websites they visit and conduct business with from their mobile devices, a performance-driven development (PDD) strategy can help companies deliver a differentiated user experience, reduce server infrastructure costs and gain a competitive advantage.
PDD is a methodology that helps development teams set Web performance testing best practices; it allows analysts and product managers to gain insight into how new features could impact Web or application performance -- and that beats learning of dissatisfaction via subpar reviews by frustrated users. PDD is complementary to test-driven development (TDD), whereby teams focus on failing test cases and writing a minimal amount of code to make the test cases pass, and behavior-driven development (BDD), which helps development teams focus on writing code that is driven by use cases.
Fine-tuning translates into dollar signs
A recent study conducted by analytics firm KISSmetrics found that customer-conversion rates can be reduced by 7% for every additional second it takes to download a webpage. Think about it for a second (pun intended): A one-second page delay on a mobile commerce site that does $100,000 in sales each day could potentially lose $2.5 million in sales every year!
A one-second page delay on a mobile commerce site that does $100,000 in sales each day could potentially lose $2.5 million in sales every year!
Front-end optimization tools like YSlow from Yahoo and PageSpeed from Google, however, have opened doors for developers to capture and analyze the anatomy of an HTTP request for a URL. The tools capture performance data such as actual page-download times, page sizes and the number of HTTP requests to load a given URL.
In addition, these tools can analyze "page goodness," or how well a given HTML page has been authored and analyzed against industry accepted Web performance testing for HTML content, producing a score on a scale of 0 to 100. A stark difference can be observed when one looks at the page goodness scores for the top-performing and bottom-performing mobile websites, as reported in Keynote Systems Inc.'s weekly Performance Index for mobile retail. Most high-performing pages have a score in the 90s on a 0-to-100 scale. Keeping all other factors constant, a page with a higher YSlow and PageSpeed score will generally perform better than a page with a lower score.
To put this to the test, I looked at the weekly mobile retail performance index for the week of Nov. 11, 2012, and analyzed the top three and bottom three mobile websites in terms of download times. The data was not surprising and is summarized below:
Top 3 Mobile Sites
Bottom 3 Mobile Sites
|Download times (lower is better)||
|# of HTTP requests (lower is better)||
|YSlow score (higher is better)||
But the tools don't stop at providing the data -- they go further by actually suggesting techniques and page-specific recommendations to optimize the content.
PDD taken a step further
Doing the static analysis and optimizing based on recommendations from tools such as PageSpeed and YSlow shouldn't be a one-off activity. Given the constant churn today's mobile websites (and hybrid apps that depend on mobile websites) go through, companies can continue to delight their customers by integrating performance monitoring as part of their continuous integration (CI) environments. Using open source tools such as HAR Storage (based on MongoDB and Python) and PhantomJS, development teams can easily integrate and automate mobile Web performance monitoring as part of their existing CI environments, such as Jenkins.
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In addition to being incorporated into the CI environment, performance data can be used to provide additional insights into customer behavior analysis done via traditional data analytics. For example, data analysts can correlate exit-pages data with performance data and determine if most users are leaving the site on a page that has a poor performance score.
The indirect benefits of Web performance testing
Optimizing performance characteristics of mobile websites has some indirect benefits as well. With more and more cellular carriers doing away with unlimited data plans, your customers will appreciate the lower data needs of your website and may choose your website over that of a competitor, all other things being equal.
Ajay Jain is a senior leader with mobile strategy and application development consulting firm Solstice Mobile in Chicago. He has more than 18 years of technology experience and specializes in mobile strategy, mobile performance engineering, mobile analytics and mobile platform solutions.