Raluca Budiu is Senior Director, Data Strategy, at Nielsen Norman Group, where she uses her data-analysis expertise to drive strategic decisions. She also serves as editor for the articles published on NNgroup.com. Raluca has coauthored many NN/g reports, as well as the book Mobile Usability. She holds a Ph.D. from Carnegie Mellon University.
Modes can be a hidden state and lead to user errors. But they can also make a user interface more efficient by allowing the same action to have different results, depending on the situation.
A confidence-interval calculation gives a probabilistic estimate of how well a metric obtained from a study explains the behavior of your whole user population.
Direct manipulation is an interaction technique in graphical user interfaces where users move depictions of objects around and get immediate feedback about their actions and the outcome of these actions.
Qualitative usability studies have few users and variable protocol; numbers obtained from such studies are likely to poorly reflect the true behavior of your population due to large measurement errors.
A survey of people in user experience and product management shows that these professionals disagree on who should be responsible for many key tasks, like doing discoveries and early design.
The Duo is a two-screen foldable mobile device that enables users to use two applications side by side, but most apps do not take advantage of the two screens. Support for information transfer from one app to the other is limited and multitasking within the same app is at times confusing.
Poorly designed qualitative or quantitative research may produce invalid results. Avoid encouraging certain responses or behaviors and make sure that your study conditions and participants are representative.
People can remember about 7 (plus/minus 2) items in short-term memory. This memory limitation has implications for UX design, but not the ones you often hear stated.
