The first crop of iPad apps may draw user approval for being "beautiful," but they also create user frustration as people try to figure out where to touch in order to interact with them, according to usability expert Jakob Nielsen whose user-experience research firm Nielsen Norman Group today released results from a usability study of 34 iPad apps.

Not only are users' hard earned web-interaction skills not transferable to iPad apps, the learning for one app does not necessarily apply to the next one. Early iPad apps are marked by inconsistent interaction design.

"It's the Wild West all over again in interaction design," Nielsen says. "We're seeing the same thing we saw 17 years ago in web design when anything a designer could draw could be a user interface whether it made sense or not. That's happening with the iPad apps. Anything you can show and touch can be a user interface on this device. There are no standards or expectations, and users just don't know what to do, or even what options exist."

Illustrating the problem of inconsistent interaction design, Nielsen Norman Group found that when study participants touched a picture or image, such as a logo, any of the following five results could happen in different iPad apps: nothing; the picture enlarges; it hyperlinks to a page with more detail; it flips over to reveal additional pictures; or a set of navigation choices pops up.

User confusion was compounded by the fact that the user interfaces on iPad apps are mostly hidden, which resulted in frequent accidental activations when users touched things by mistake or made a gesture that unexpectedly initiated a feature. Making things worse, people didn't know how to revert to the previous state because there is no consistent "undo" feature to provide an escape hatch like the Web's "Back" button.

"When we asked our study participants for their first impressions of many iPad apps, the word they gave most often was 'beautiful.' Still, we think that beauty shouldn't have to come at the cost of being able actually to use the apps to derive real benefits from their features and content," adds lead researcher Raluca Budiu, Nielsen Norman Group user experience specialist.

Study participants in Nielsen Norman Group's research were observed interacting with 34 iPad apps, and in some cases with their related websites. Included in the study were apps and sites such as AP News, Time Magazine, USA Today, ESPN.com, MLB and Nike.com. The research report, entitled "Usability of iPad Apps and Websites. First Research Findings” and co-authored by NN/g user experience specialist Raluca Budiu and Jakob Nielsen is available to download for free from the Nielsen Norman Group website at http://www.nngroup.com/reports/mobile/ipad/ .