Wikipedia
Usability testing is a means for measuring how well people can use some human-made object (such as a web design web page, a computer user interfaceinterface, a document, or a device) for its intended purpose, i.e. usability testing measures the usability of the object. Usability testing focuses on a particular object or a small set of objects, whereas general human-computer interaction studies attempt to formulate universal principles.If usability testing uncovers difficulties, such as people having difficulty understanding instructions, manipulating parts, or interpreting feedback, then developers should improve the design and test it again. During usability testing, the aim is to observe people using the product in as realistic a situation as possible, to discover errors and areas of improvement. Designers commonly focus excessively on creating designs that look "cool", compromising usability and functionality. This is often caused by pressure from the people in charge, forcing designers to develop systems based on management expectations instead of people's needs. A designers' primary function should be more than appearance, including making things work with !people.Cauti on:? simply gathering opinions is not usability testing -- you must arrange an experiment that measures a subject's ability to use your document. jerz.setonhill.edu - 1 Rather than showing users a rough draft and asking, "Do you understand this?", usability testing involves watching people trying to ''use'' something for its intended purpose. For example, when testing instructions for assembling a toy, the test subjects should be given the instructions and a box of parts. Instruction phrasing, illustration quality, and the toy's design all affect the assembly process.Setting up a usability test involves carefully creating a scenario, or realistic situation, wherein the person performs a list of tasks using the product being tested while observers watch and take notes. Several other test instruments such as scripted instructions, paper prototypes, and pre- and post-test questionnaires are also used to gather feedback on the product being tested. For example, to test the attachment function of an e-mail program, a scenario would describe a situation where a person needs to send an e-mail attachment, and ask him or her to undertake this task. The aim is to observe how people function in a realistic manner, so that developers can see problem areas, and what people like. The technique popularly used to gather data during a usability test is called a think aloud protocol.
What to measure - Usability testing generally involves measuring how well test subjects respond in four areas: time, accuracy, recall, and emotional response. The results of the first test are the baseline or control measurement; all subsequent tests are compared to the baseline.''Time on Task'' -- How long does it take people to complete basic tasks? (For example, find something to buy, create a new account, and order the item.)''Accuracy'' -- How many mistakes did people make? (And were they fatal or recoverable with the right information?)''Recall'' -- How much does the person remember afterwards?''Emotional Response'' -- How does the person feel about the tasks completed? (Confident? Stressed? Would the user recommend this system to a friend?)In the early 1990s, Jakob Nielsen (usability consultant)Jakob Nielsen, at that time a researcher at Sun Microsystems, popularized the concept of using numerous small usability tests -- typically with only five test subjects each -- at various stages of the development process. His argument is that, once found that two or three people are totally confused by the home page, little is gained by watching more people suffer through the same flawed design. "Elaborate usability tests are a waste of resources. The best results come from testing no more than 5 users and running as many small tests as you can afford." useit.com - 2. Nielsen subsequently published his research and coined the term heuristic evaluation.The claim of "Five users is enough" was later described by a mathematical model (Virzi, R.A., Refining the Test Phase of Usability Evaluation: How Many Subjects is Enough? Human Factors, 1992. 34(4): p. 457-468.) which states for the proportion of uncovered problems Uwhere p is the probability of one subject identifying a specific problem and n the number of subjects (or test sessions). This model shows up as an asymptotic graph towards the number of real existing problems (see figure below). In later research Nielsen's claim has eagerly been questioned with both empirical evidence citeseer.ist.psu.edu - 3 and more advanced mathematical models (Caulton, D.A., Relaxing the homogeneity assumption in usability testing. Behaviour & Information Technology, 2001. 20(1): p. 1-7.). Most researchers today agree that in many applications a sample size quite larger than five is required to detect a satisfying amount of usability problems.Bruce Tognazzini advocates ''close-coupled testing'': "Run a test subject through the product, figure out what's wrong, change it, and repeat until everything works. Using this technique, I've gone through seven design iterations in three-and-a-half days, testing in the morning, changing the prototype at noon, testing in the afternoon, and making more elaborate changes at night." asktog.com - 4 This testing can be useful in research situations
See also - Software testing Educational technology
External links - public.asu.edu - High Coverage Usability testing usability.gov - Usability.gov Jakob Nielsen: useit.com - UseIT.com Dennis G. Jerz: jerz.setonhill.edu - Why Usability Testing Matters: Palm Beach County Ballot Design Bruce Tognazzini: asktog.com - How to Deliver a (Usability) Report Without Getting Lynched John S. Rhodes: webword.com - WebWord: Usability and Human Factors on the Internet Usableweb.com - Usableweb tc.eserver.org - EServer TC Library: Usability Testing Lyle Kantrovich: crocolyle.blogspot.com - Croc O' Lyle www-306.ibm.com - IBM: Ease of UseCategory:Human-computer interactionCategory:Software testingCategory:Educational technology
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Websites
Digital Inkwell
Digital Inkwell Inc provides Documentation and Training expertise ranging from early stage Requirements Analysis to end-of-cycle Evaluation and Improvement.
http://www.digitalinkwell.ca/
HCI Bibliography
The HCI Bibliography (HCIBIB) is a free-access bibliography on Human-Computer Interaction, with over 33,000 records in a searchable database. HCIBIB.ORG is also one of the premier portals to high-quality information on the development of usable software and Web-based systems.
http://www.hcibib.org/
Useit.com
Jakob Nielsen shares his thoughts on usability.
http://www.useit.com
Amazon.com
Departments include books, music, videos, home and garden, electronics, and toys.
http://www.amazon.com/
Sun Microsystems, Inc.
Provides products, services and support solutions for building and maintaining network computing environments. Designs, manufactures and sells UNIX-based workstation computers, storage devices, and servers. (Nasdaq: SUNW).
http://www.sun.com/
U.S. Dept. of Labor -- Bureau of Labor Statistics
Official website of Bureau, with news, current data, articles, links and other information about employment, wages, working and the economy
http://www.bls.gov/
Usability.gov
Provided by the National Cancer Institute. Includes information and resources on making web sites and other user interfaces more useful, usable, and accessible. News and current publications and additional links are provided.
http://www.usability.gov/
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