Nielsen Norman GroupEvidence-Based User Experience Research, Training, and Consulting
Because applications must help people complete tasks (rather than just consume information,) they often magnifiy ordinary usability challenges. Below you'll find tips on everything from labeling commands to organizing steps in a logical workflow -- all gleaned from our first-hand research with real application users.
For more in-depth analysis of application design and usability:
Winning app UIs include domain-specific solutions that allow humans to focus on deeper issues while the software takes care of the mechanics.
Smooth-flow task performance makes application use pleasurable. But disruptions are all too common due to crinkly design or creaking implementation.
'Chrome' is the user interface overhead that surrounds user data and web page content. Although chrome obesity can eat half of the available pixels, a reasonable amount enhances usability.
Overloading different outcomes on similar commands can be confusing. Using the same command for multiple actions enhances usability if the results are conceptually the same.
Actions at one step of an application impact subsequent steps. When users don't understand this relationship, usability suffers.
It's more difficult to conduct usability studies with experienced users than with novices, and the improvements are usually smaller. Still, improving expert performance is often worth the effort.
Websites that let users customize the UI have the same measured usability as regular sites. Sites for customizing products, however, score substantially worse due to complex workflow.
Many winners employ dashboards to give users a single overview of complex information and use lightboxes to ensure that users notice dialogs. Also, the Office 2007 ribbon showed surprisingly strong early adoption.
Should the OK button come before or after the Cancel button? Following platform conventions is more important than suboptimizing an individual dialog box.
Application usability is enhanced when users know how to operate the UI and it guides them through the workflow. Violating common guidelines prevents both.
Applications can give users access to a richer feature set by using the same few commands to achieve many related functions.
13 design guidelines for tab controls are all followed by Yahoo Finance, but usability suffers from AJAX overkill and difficult customization.
The more engaged users are, the more features an application can sustain. But most users have low commitment -- especially to websites, which must focus on simplicity, rather than features.
Interaction techniques that deviate from common GUI standards can create usability catastrophes that make applications impossible to use.
Application commands can be presented as buttons or as links, which offer more room for explanation. For primary commands, however, buttons are still best.
Progressive disclosure defers advanced or rarely used features to a secondary screen, making applications easier to learn and less error-prone.
Macintosh-style interaction design has reached its limits. A new paradigm, called results-oriented UI, might well be the way to empower users in the future.
Once an online form goes beyond two screenfulls, it's often a sign that the underlying functionality is better supported by an application, which offers a more interactive user experience.
Despite posing well-known risks, websites continue to feature poorly designed scrollbars. Among the ongoing problems that result are frustrated users, accessibility challenges, and missed content.
A field study identified twenty-two ways that automated hospital systems can result in the wrong medication being dispensed to patients. Most of these flaws are classic usability problems that have been understood for decades.
User interface guidelines for when to use a checkbox control and when to use a radio button control. Ten other usability issues for checkboxes and radio buttons.
Usability tests of 46 Flash applications identified basic issues related to the ephemeral nature of Web-embedded apps. Some findings restate old truths about GUIs; others reflect the Net's new status as nexus of the user experience.
Established wisdom holds that good error messages are polite, precise, and constructive. The Web brings a few new guidelines: Make error messages clearly visible, reduce the work required to fix the problem, and educate users along the way.
The Internet is undoing the industrial revolution's emphasis on mass-produced products; now everybody can get exactly what they want. But designing the product you want is hard, and current design interfaces are not good enough for novice designers (i.e., all normal customers).
Most Web forms would have improved usability if the Reset button was removed. Cancel buttons are also often of little value on the Web.
Instead of making users wander indefinitely and frustratingly around a site looking for something that's just not there, tell them if it lacks a frequently requested feature
Applets are divided into two categories: functionality applets that need to open in a new window and content applets that should stay on the browser page.
Designing for the Web is different from traditional user interface design. Fundamentally, the designer gives up a lot of control to the user - get used to it: WYSIWYG is dead
All usability studies show that fast response times are essential for Web usability: let's believe the data for once! Advice for speeding up sites despite the fact that bandwidth is going down, not up.
We reverse all of the core design principles behind the Macintosh human interface guidelines to arrive at the characteristics of the Internet desktop.
This excerpt from Jakob Nielsen's book Usability Engineering describes how users react to different response time delays.
The concept of direct manipulation is usually viewed as a single characteristic of a class of interaction styles. Here, direct manipulation is analyzed according to a detailed layered interaction model, showing that it has quite different effects on the dialogue on the different levels. In particular, the "no errors" claim may be true at the syntax level but not at several of the levels above or below that level. Furthermore, a unified framework is presented for conceptualizing Direct Manipulation, What You See Is What You Get (WYSIWYG), Transparency, Immediate Command Specification, Arcticulatory Directness, and Computational Appliances according to a layered interaction view.
User interface standards can be hard to use for developers. In a laboratory experiment, 26 students achieved only 71% compliance with a two page standard; many violations were due to influence from previous experience with non-standard systems. In a study of a real company's standard, developers were only able to find 4 of 12 deviations in a sample system, and three real products broke between 32% and 55% of the mandatory rules in the standard. Designers were found to rely heavily on the examples in the standard and their experience with other user interfaces. Thovtrup, H., and Nielsen, J. (1991). Assessing the usability of a user interface standard. Proc. ACM CHI'91 Conf. Human Factors in Computing Systems (New Orleans, LA, 28 April-2 May), 335-341.