• by Mark Walsh  @markfwal, November 24, 2010

Research firms have already predicted a big uptick in shopping via mobile device this holiday season. IDC, for instance, has projected that mobile shopping "Warriors" and "Warrior Wannabees" spending through all channels including mobile will account for 28%, or $127 billion, of the $447 billion the National Retail Federation forecasts that U.S. consumers will spend over the coming weeks.

But a new seasonal index from Web performance-tracking service Compuware Gomez suggests that mobile shoppers will have to overcome the frustration of slow-loading or crashing sites to browse and buy items on handsets during the holidays.

The online index created by Gomez compares the performance among the top 500 Web retail Web sites (as determined by trade publication Internet Retailer) with the top 15 retail sites from that group, and their corresponding mobile sites. The top 15 includes companies such as Amazon, Dell, Macy's, Sears, Target and Walmart.

Starting Wednesday and running through Cyber Monday (Nov. 29), Gomez's automated tracking system early on showed that the top 15 mobile sites as a group were performing poorly based on how long it takes for a Web or mobile page to load, the availability of the page and the consistency of response time.

In a rating scale in which 94 and above is considered excellent, 85 to 94 is good, and 70 is fair, the top 15 mobile sites as a group had a score of 48.

That compares to 66 for the Internet Retailer 500 and 85 for the PC-based Web sites of the top 15 retailers. Obviously, it shows a huge gap between their desktop and mobile sites. That's not a huge surprise in light of a Gomez study last year, which found that two of three mobile Web users reported having problems when visiting Web sites on their mobile phones.

Prior Gomez research has shown that an increase in Web page response time from two to 10 seconds increased page abandonment rates by 38%. And Forrester Research has found the average online shopper expects Web pages to load in two seconds or less, down from four seconds in 2006. And consumers' standards for mobile sites are not necessarily lower.

Most cell phone users surveyed by Gomez last year said they expect sites to load almost as quickly, as quickly, or even faster on their mobile phone than their home or work computer. The proliferation of smartphones in the last year, which Nielsen estimates have reached 28% penetration among mobile users in the U.S., would suggest more people have a better mobile Web experience now.

But the performance of the top 15 mobile retail sites in the Gomez index indicates that things have not improved much this year. So any gains in m-commerce spending this holiday season will likely come despite difficulties navigating mobile sites or through alternate shopping tools like mobile apps.