Usability Tests and Heuristic Evaluations in Assessing Prototypes of Essay

Usability Tests and Heuristic Evaluations in Assessing Prototypes of Interface Designs - Essay Example Effectiveness is described as the degree of consistency that a product will behave as expected. It is also the measure the degree of ease users experience in using the product. Learnability refers to the ability of the user to operate the system with a definite degree of competence after a certain amount of training. It also refers to likelihood that users who have not used the system for a period of time will be able to relearn how to operate it. Satisfaction includes a user’s feelings, perceptions, and opinion about the system. Information is usually collected through written and oral means (Rubin & Chisnell 2008). Finally, accessibility involves the capability of the system to allow persons with disabilities to perceive, understand, navigate, and interact with it. In performing usability tests, two basic principles should always be remembered: (1) a designer’s perception on the system design is different from the target audience; and (2) it is better to conduct multi ple tests with a few users rather than running a single test with a large number of users. Usability tests usually involve either getting an audience evaluation of the system or having a usability design expert perform a heuristic evaluation of the program. One drawback of heuristic evaluation is that the expert reviewer may not share the same perception as the target users or may identify errors that target users do not consider as problems. In contrast, an audience evaluation of the system is a credible representation of a real-world user’s needs and perceptions of the system... of determining the ideal number of users to comprise a usability test group, the following guidelines are recommended: (1) too few users yield inferior results since the users may not be able to identify most of the problems; and (2) too many users would increase the chance that most users would identify the same problem and reduces the chances that the users will be able to identify less obvious errors (Silver 2005). There are four types of usability tests which a developer may choose from depending on the situation: (1) exploratory; (2) assessment; (3) evaluation; and (4) comparison. Exploratory testing is usually performed in the early part of the design stage. It has to primary objectives. First, to verify of the functions selected to be used in the system are useful and appropriate for the user. Second, to determine the degree as to which the system design matches the user’s mental model of the system. A mental model is described as a user’s assumptions and expecta tions regarding how certain tasks are accomplished (Silver, 2005). One important feature of an exploratory test is the high degree of freedom a developer can attain in developing early designs of the system. By using tools such as paper screens and system prototypes with limited functionalities, the developer can collect important information and feedback from the users. This allows the developer to determine if the initial design matches user perception of the system. In addition, exploratory tests enable developers to detect serious flaws in the design before a mode concrete plan of the system is created (Rubin & Chisnell, 2008). In an exploratory test, a moderator may provide the user with screenshots of the system and ask if all the types of information or functions that the user expected to be