The Difficulty of Comparisons
Comparing information about two or more options is a much more difficult task than simply finding information about each of the options, and most sites are not designed to help users perform such comparisons.
Strategies used by individuals asked to compare products:
- Memory - Some users would try to rely on memory to record the salient points, but this resulted in a lot of going back-and-forth to product pages, as well as a lot of inaccurate answers
- Notes - Some individuals resorted to using pan-and-paper to record salient details for comparisons
- Printing - Users would often print out Web pages to compare products, but it was noted that, a majority of the time, they did not waver from the decision they had made prior to reviewing the print-outs. EN: I wonder if the "printing" option is as common in situations where the user must pay for the paper and toner, as opposed to the "free" print-outs they were getting in the test lab.
- Multiple Windows - Some of the more experienced users would opne multiple browser windows to do on-screen comparisons. EN: I wonder if "tabbed" browsing, which is facilitated by current software, is often used.
A behavior seen frequently was "pogo-sticking" - where users would start from a menu, navigate down, jump back to the menu, navigate back to the next option, then back to the menu, etc. - was common, even where sites provided links among pages with similar products.
Spool's remarks about the pogo-stick behavior are neutral, though a number of other sources have cited this study to that it is undesirable behavior that site designers should attempt to overcome. Seems clear to me that the implication is that users are going to behave this way, even if links are provided to navigate horizontally, and there's nothing that can be done to discourage it.
Some sites provide options that enable users to do comparisons on a single screen - such as travel sites showing several flights in a timetable. This was deemed useful, but in some instances, users were distrustful (they felt that the options were presented in a manner to steer them to the one that was most profitable for the vendor to sell).
They also point to an example of the "decision engine" that allows users to answer a few basic questions about their needs, then shows them a table of options that best suit their needs. The author suggests that this seems helpful, but admits that "we haven't tested this, so we don't know if it actually helps."