The above is the title of a new post this week by Jakob Nielsen. Here is the link: http://www.useit.com/alertbox/mobile-content-comprehension.html. The study he refers to is one that applied the Cloze test to the privacy policies of a number of websites. The key finding: comprehension for iPhone readers is 48% of what is on a PC. The small screen is a killer.
Obviously this has major implications for mobile surveys. Mobile enthusiasts are almost always careful to caution that screen real estate is an issue and what we do online cannot be what we do on mobile devices Nielsen offers a nice factoid to use against questionnaire designers who don't get it. So remember that number.
P.S. My apologies for not embedding the link. I'm writing from my iPad and the Typepad editor is less than fully functional.