Glossary » Usability Methods
clinical trial
testing a system in a clinical setting; that is, in a hospital, clinic, doctor’s office, etc. User testing and feature testing in such an environment has special limitations, especially because of the potential for unexpected effects on patient care. User…
Read more »closed card sort
a type of card sort that asks users to sort topics into pre-defined categories, as opposed to asking the users to label the categories. Users are provided with a list of topics (e.g. content pieces to go on a website)…
Read more »clown-invariant research design
an empirical study designed to be sufficiently robust, both in the effect being studied and in the method of the study, that you get the same results even if the investigator is wearing a clown suit.
Read more »CMN-GOMS
Card, Moran, and Newell GOMS. CMN-GOMS adds hierarchical structure to the Keystroke Level Model (KLM) version of GOMS. Tasks are organized as a series of goals and subgoals and operators are organized into subroutines called methods. CMN-GOMS can provide task…
Read more »co-discovery method
also “constructive interaction”; a user-testing technique where users work collaboratively to solve problems on a computer. The advantage over single-person testing is that the users talk about what they are doing naturally (as opposed to using a think-aloud protocol) and…
Read more »coaching method
an approach to usability testing that involves a user and an expert coach. Instead of disallowing questions, users are encouraged to ask questions of the coach, who responds with appropriate instruction. By hearing typical user questions, problems are identified and…
Read more »cognitive modeling
producing a computational model for how people perform tasks and solve problems, based on psychological principles. These models may be outlines of tasks written on paper or computer programs which enable us to predict the time it takes for people…
Read more »cognitive walkthrough
an approach to evaluating a user interface based on stepping through common tasks that a user would need to perform and evaluating the user’s ability to perform each step. This approach is intended especially to help understand the usability of…
Read more »collaborative inquiry
Inquiry is the investigation of users and their context in order to understand their problem space, their goals, and associated design constraints, usually by observational methods, surveys, and interviews. Collaborative inquiry involves the users (or potential users) of an application…
Read more »comp
(graphic design) a rapidly-drawn but high-quality sketch intended for presentation purposes. Traditionally comps are created as quick color sketches done in marker, often used for client presentations especially in advertising and architecture. A comp is usually intended to be a…
Read more »comparative study
a study whose purpose is to compare 2 or more products, such as a user testing comparison to make sure that a new version of a product has fewer problems than the prior version. Another type of comparison is a…
Read more »competitive analysis
a set of methods for getting ideas from your competition, whether through reverse-engineering their user interface design rationale, determining common user interface conventions, or finding usability problems that can be fixed.
Results of a competitive analysis can be used in…
Read more »competitive user testing
a comparison of 2 or more user interfaces from competitive products used for marketing or product design purposes. When used for marketing, fairly rigorous procedures must be applied to ensure the accuracy and credibility of the result.
Read more »complaint tracking
taking user complaints and categorizing them for later followup in improving a user interface. Particularly common for websites, where complaints usually arrive through email and may come in large numbers. Complaints are categorized and prioritized (in a kind of triage…
Read more »confidentiality
in collecting data in user studies, confidentiality guarantees a person that their data will not be released in a way that it can be tracked to them as an individual. Anonymity is slightly different, in that it guarantees that a…
Read more »confound
any factor that might serve as an alternative (and generally undesirable) explanation for a result seen in a study, such as non-randomized samples, practice and history effects, and any arbitrary differences between things that are being compared.
Read more »consistency inspection
a quality control technique for evaluating and improving a user interface. The interface is methodically reviewed for consistency in design, both within a screen and between screens, in graphics (color, typography, layout, icons), text (tone, style, spelling), and interaction (consistency…
Read more »construct validity
the degree to which the testing tool and measurement tool used in a study accurately reflect the conceptual question of interest. For instance, asking people whether they feel that a product is usable is not necessarily an accurate measure of…
Read more »contextual inquiry
a structured technique for gathering field data through interviewing (in a participatory design sense) and collecting information about the environment (the context).
Read more »conversation analysis
a technique generally used for analyzing multi-user interactions, such as spoken conversations in a meeting. Conversation analysis is focused on detailed analysis of naturalistic transcripts of conversations.
Read more »cost-benefit analysis
a comparison of the cost of a new system to the benefits of its use. This helps to evaluate the value of adopting new computer equipment and also to evaluate the merits of performing usability analyses and redesigning a user…
Read more »cost-effectiveness evaluation
a comparison of the cost of implementing a new information system or upgrading an existing one to the costs that would be involved in retaining the existing way of doing things (i.e. the legacy system or the non-computerized approach). A…
Read more »counterbalancing
A technique in experimental design that is used to avoid the introduction of confounding variables. In usability testing, this technique is most commonly used when establishing task order.
For example, a website user test might ask…
Read more »CPM-GOMS
Cognitive Perceptual Motor GOMS. CPM-GOMS is a cognitive modeling technique based on CMN-GOMS with an emphasis on parallel activities. Where other GOMS techniques assume that humans do one thing at a time, CPM-GOMS assumes as many operations as possible will…
Read more »criterion testing
user testing that measures user performance to determine whether a target performance level has been reached. Typically a project will begin by determining usability requirements in terms of target performance along various benchmarks, e.g. “starting from the website homepage, the…
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