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The 960 Grid System is an effort to streamline web development workflow by providing commonly used dimensions, based on a width of 960 pixels. There are two variants: 12 and 16 columns, which can be used separately or in tandem.
Marielle's little place on the web
about usability, cognition, neuroscience, psychology, learning, interface design, ergonomics, and other interesting thingsBrowsing Posts published by marielle
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Quantifying the user experience through the statistical analysis of human behavior.
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The Web Design Sketchbook is a set of website tools to
help through the process of planning and designing your web projects. The Sketchbook starts with a set of design and content planning questions that cover everything from site objectives, design tone to the information architecture or sitemap.The book the features a series of design and layout brainstorming pages with full browser chrome and grids to better plan how your site will look and operate when it is finished. The book features thumbnail, detail and full page sizes for more efficient brain storming and detail development.
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The UX Bookmark is a resource for HCI and human factors professionals, usability engineers, interaction designers & information architects.
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This weblog explores the symbiotic relationship between creative design and the field of information visualization. More specifically, it collects projects that represent data or information in original or intriguing ways.
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About wireframes: samples, tools, templates, inspirations, experimental.
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Documentation on developing for Safari. Includes specific how-to's for safari on iphone.
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The Public Sphere Project (PSP) is an initiative of Computer Professionals for Social Responsibility (CPSR) to help promote more effective and equitable public spheres all over the world. The Public Sphere Project is intended to provide a broad framework for a variety of interrelated activities and goals. With pattern library.
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Application that visualizes mouse activity (path, stops, clicks).
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Extensive pattern library
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User Interface Design patterns are recurring solutions that solve common design problems. Design pattern articles and screenshot examples.
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Social Visualization Patterns is a library of interaction design patterns for the implementation of a visualization centered social space.
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Large American oral history project. The heart of StoryCorps is the conversation between two people who are important to each other: a son asking his mother about her childhood, an immigrant telling his friend about coming to America, or a couple reminiscing on their 50th wedding anniversary.
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A collective telling of the events of 9/11 through the eyes of those who experienced it, both at the attack sites and around the world.
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Four prototypes of digital cameras, each with a different interaction style. The interaction styles range from rich to conventional.
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UX patterns, with for each pattern: problem, solution, context, rationale, implementation, examples and sources
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xtimeline is a free web-based timeline. Easily create and share timelines with pictures and videos.
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InterPlay is a platform for designers in the Media Lab to create dynamic social simulations, which transform public spaces into immersive environments where people become the central agents. It utilizes computer vision and projection to facilitate full body interaction with digital content.
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Mouseless consists of an Infrared (IR) laser beam (with line cap) and an Infrared camera. Both IR laser and IR camera are embedded in the computer. The laser beam module is modified with a line cap and placed such that it creates a plane of IR laser just above the surface the computer sits on. The user cups their hand, as if a physical mouse was present underneath, and the laser beam lights up the hand which is in contact with the surface.
How many people are needed for a usability study? The question comes up time and time again, with different answers. This time, Hwang and Salvendy have tried to answer it by a meta-analysis of the available literature since 1990. As inclusion criteria they used:
- the usability evaluation was done with one of the methods think-aloud, heuristic evaluation or cognitive walkthrough
- the study reported the number of participants in the evaluation (users or evaluators) and the overall discovery rate of errors.
Out of the 102 usability evaluation experiments found, only 27 satisfied the inclusion criteria. Hwang and Salvendy then performed a linear regression analysis on the data, and tried to estimate the number of people needed to detect 80% of the usability problems. The results: 9 for think-aloud, 8 for heuristic evaluation and 11 for cognitive walkthrough. This leads them to propose 10±2 as a rule of thumb.
I have a few problems with this approach. The ‘how many users’ question is a very logical question to ask, both when planning a study and when interpreting the results. But the statistical analyses are just numbers, and to determine the real value of a study one should not forget the content.
- Not all errors are equal. While 80% detection sounds good, issue severity should not be neglected. Hwang and Salvendy mention that the cognitive walkthrough method is good at finding critical issues, but less adequate for detecting minor flaws. Knowing that, I wouldn’t choose for increasing the number of evaluators to 11 (!), but would rather combine a smaller early cognitive walkthrough with another evaluation method later, maybe even on a fixed prototype. If 2 or 3 evaluators using the cognitive walkthrough method can point to some of the severe issues, this is valuable enough in itself.
- Issues are not always errors. A usability evaluation can help discover potential problems, but the way these issues influence the user experience and user behavior in real life may not be the same as in the user study.
- The usefulness of your results depends on how they are used. Using the results wisely to improve the next design iteration of a system is useful. Using them to formulate specific questions to be answered with other methods (think of A/B testing for example), or to decide on what data to collect, makes sense too. But using them to calculate a magic number to report to stakeholders (based on ‘few issues found = good system’) makes less sense.
Besides, what does that 80% number mean? 80% of the total number of issues hidden in a system, but that’s not a real, measurable quantity. Okay, when the number of distinct issues found is plotted against the number of participants used, the curve does flatten and an upper limit can be estimated. But even with very large groups, there is still a chance that one more participant will find something that all of the others overlooked. In addition, the characteristics of the participants and the protocol used also influence which types of issues will be found easily.
However, I think that in practice the 10±2 guideline should work pretty well, especially for the think-aloud case with non-expert users. With a very small group of users, it is often difficult to say if the findings will generalize across the real user base. On the other hand, using a very large amount of people is costly in time and money, and does not have much added value since there will be lots of repetition in your findings.
Hwang, W., & Salvendy, G. (2010). Number of people required for usability evaluation Communications of the ACM, 53 (5) DOI: 10.1145/1735223.1735255
