Nielsen Norman GroupEvidence-Based User Experience Research, Training, and Consulting
Should the OK button come before or after the Cancel button? Following platform conventions is more important than suboptimizing an individual dialog box.
Lists of links are an intermediate case between content-embedded links and menu items. Showing listed links in blue or in the site's main link color is the recommended design - and the one most intranets follow.
A site did most things right, but still had a miserable 14% success rate for its most important task. The reason? Users ignored a key area because it resembled a promotion.
Interaction techniques that deviate from common GUI standards can create usability catastrophes that make applications impossible to use.
A remarkable 80% of findings from the Web usability studies in the 1990s continue to hold today.
A strict focus on accessibility as a scorecard item doesn't help users with disabilities. To help these users accomplish critical tasks, you must adopt a usability perspective.
About 90% of usability guidelines from 1986 are still valid, though several guidelines are less important because they relate to design elements that are rarely used today.
Users expect 77% of the simpler Web design elements to behave in a certain way. Unfortunately, confusion reigns for many higher-level design issues.
People get lost and move in circles when websites use the same link color for visited and new destinations. To reduce navigational confusion, select different colors for the two types of links.
Over the last 1.5 years, the average compliance with established usability guidelines increased by 4%. If we can sustain this level of improvement, we'll reach the ideal of 90% guideline compliance in 2017.
Anything done by more than 90% of big sites becomes a de-facto design standard that must be followed unless an alternative design achieves 100% increased usability.
Standards ensure a consistent vocabulary, but don't limit designers' freedom (and responsibility) in deeper design issues. Also: Guidelines for writing design standards.
The 10 most general principles for interaction design. They are called "heuristics" because they are more in the nature of rules of thumb than specific usability guidelines.
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.