Making the Numbers Work
Meanwhile, rather than testing one variable, coupling tests the effectiveness of an entire conversion clickpath, or a large part of a clickpath. On-site, for example, A/B testing might mean getting the best homepage, product page, and checkout page out of all your options; coupling would determine the best homepage/product page/checkout page combination.
Metrics tracking comes with two major challenges, one technical, one creative. Cookie deletion is the technical issue. Because of growing consumer fears of privacy violations, an increasing number of computer users delete their cookies regularly, regardless of who the cookies are from. According to a 2005 study by Jupiter Research, "Measuring Unique Visitors: Addressing the Dramatic Decline in the Accuracy of Cookie-Based Measurement," close to 40 percent of all Internet users delete their cookies monthly. This threatens to seriously skew metrics tracking results, as cookies traditionally have been used to answer basic questions such as, "Is my visitor a repeat visitor?"—not to mention more complex questions such as, "What has this visitor done on my site before?" and, "What kinds of things would this visitor like to see?" A number of solutions to this problem are being implemented, such as relying more heavily on records of visitor ISPs rather than on cookies placed on computers.
One technical solution many marketers have turned to is flash-based cookies (as opposed to HTML-based). Flash-based cookies are much harder to remove. However, some metrics recording experts suggest that until the unremovable cookie is introduced, Web statistics recorders should simply assume that the numbers they're looking at are too small, and that trackers should add and multiply accordingly.
On the creative side, the danger is leaving nothing to human creativity. Metrics can tell you what works and what doesn't, but there are certain elements of the picture that might best be left a mystery. In other words, rely too heavily on the numbers and not enough on your instincts, and you could be missing out on opportunities to hit site visitors at gut-level. On the other hand, leaving too much untracked could lead to poor results. For instance, if you can't see how many visitors go to your shopping cart, you don't know how well your online store is doing.