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User-centered design (UCD) oruser-driven development (UDD) is a framework of processes in whichusability goals, user characteristics,environment, tasks and workflow of aproduct, service or brand are given extensive attention at each stage of thedesign process. This attention includes testing which is conducted during each stage of design and development from the envisionedrequirements, through pre-production models to post production.[1][2]
Testing[3] is beneficial as it is often difficult for the designers of a product to understand theexperiences of first-time users and each user'slearning curve. UCD is based on the understanding of a user, their demands, priorities and experiences, and can lead to increased product usefulness and usability.[4] UCD applies cognitive science principles to create intuitive, efficient products by understanding users' mental processes, behaviors, and needs.
UCD differs from other product design philosophies in that it tries to optimize the product around how users engage with the product, in order that users are not forced to change their behavior and expectations to accommodate the product. The users are at the focus, followed by the product's context, objectives and operating environment, and then thegranular details of task development, organization, and flow.[2][3]
The termuser-centered design (UCD) was coined by Rob Kling in 1977[5] and later adopted inDonald A. Norman's research laboratory at theUniversity of California, San Diego. The concept became popular as a result of Norman's 1986 bookUser-Centered System Design: New Perspectives on Human-Computer Interaction[6] and the concept gained further attention and acceptance in Norman's 1988 bookThe Design of Everyday Things, in which Norman describes the psychology behind what he deems 'good' and 'bad' design through examples. He exalts the importance of design in our everyday lives and the consequences of errors caused by bad designs.
Norman describes principles for building well-designed products. His recommendations are based on the user's needs, leaving aside what he considers secondary issues like aesthetics. The main highlights of these are:
In a later book,Emotional Design,[7]: p.5 onwards Norman returns to some of his earlier ideas to elaborate what he had come to find as overly reductive.
The UCD process considers user requirements from the beginning and throughout the product cycle. Requirements are noted and refined through investigative methods including: ethnographic study,contextual inquiry, prototype testing,usability testing and other methods. Generative methods may also be used including:card sorting,affinity diagramming and participatory design sessions. In addition, user requirements can be inferred by careful analysis of usable products similar to the product being designed.
UCD takes inspiration from the following models:
The following principles help in ensuring a design is user-centered:[11]
The goal of UCD is to make products with a high degree ofusability (i.e., convenience of use, manageability, effectiveness, and meeting the user's requirements). The general phases of the UCD process are:[13][14]
The above procedure is repeated to further refine the product. These phases are general approaches and factors such as design goals, team and their timeline, and environment in which the product is developed, determine the appropriate phases for a project and their order. Practical models include thewaterfall model,agile model or any othersoftware engineering practice.
There are a number of tools that are used in the analysis of UCD, mainly: personas, scenarios, and essential use cases.
During the UCD process, the design team may create apersona, an archetype representing a product user which helps guide decisions about product features, navigation, interactions, and aesthetics. In most cases, personas are synthesized from a series ofethnographic interviews with real people, then captured in one- or two-page descriptions that include behavior patterns, goals, skills, attitudes, and environment, and possibly fictional personal details to give it more character.[15]