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Task Analysis

The concept of a task is central to user-centered system design and many task analysis techniques have been developed. These techniques are one of the most important steps in the Design Thinking process. They focus on different aspects of tasks such as the task structure, the ease of learning a task or the knowledge users require in order to accomplish a task. TA can help designers not just in identifying where opportunities to improve the user experience exist but also to generate some preliminary ideas as to how you might approach these challenges.


There are techniques aimed at obtaining descriptions of what people do, representing those descriptions, predicting difficulties, and evaluating systems against usability or functional requirements. Other TA techniques are concerned with predicting performance, measuring system complexity, measuring learnability, or the transfer of knowledge between systems.


Task analysis has arisen out of work in ergonomics psychology and software engineering and is concerned with what people do to get things done. Tasks are generally considered to be meaningful for the user in that users believe it to be necessary and/or desirable to undertake tasks. The term "task" embodies an intentional, or purposeful, level of description that is absent in the concept of function. In addition to undertaking tasks, users also perform actions or operations, such as pressing a key on a keyboard or moving a mouse. These would not be considered tasks since they are devoid of any control structure; they do not require thought. Task analysis techniques may be grouped together in various ways, but probably the most important distinction is whether the technique aims to represent the cognition, practice, or logic of the task.



Goals, tasks, and actions

The terms "goal" and "task" are sometimes used as synonyms, in order to remove some confusion, we will conceptualize HCI at the three levels: Goals, tasks, and actions. A goal (also called an external task) may be defined as a state of a system that the human wishes to achieve. For example, a human wants to write a letter. A goal is achieved using some instrument, method, agent, tool, technique, skill, or, generally, some device that is able to change the system of the desired state. For example, writing a letter can be accomplished using a device such as a laptop, or pen and paper. Given that the person has formed a goal, the person selects a device that will enable him or her to achieve that goal. Thus, we can define the task (or internal task) as the activities required, used, or believed to be necessary to achieve a goal using a particular device. A task is a structured set of activities in which actions are undertaken in some sequence. Tasks are what the human has to do in order to accomplish a goal. At some point, the human physically interacts with a device by performing an action (or operation). For example, the person types a command on a keyboard. An action is defined as a task that involves no problem solving or control structure component.


Goals, tasks, and actions will be different for different people, depending on their previous experience and knowledge, and on their perception and conception of the system. Other terms commonly used in task analysis include objects and methods. A method (also called a plan) consists of a number of tasks or actions linked into a sequence. This sequence may also include the provision for tasks or actions to be repeated (called iteration) or alternatives to be available at various points (selection). Objects are generally seen to be the focus of actions.












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