The third allocation strategy is to allocate each function in a way that maximizes economicefficiency.

The second allocation strategy is assigning each function to the most capable agent, which canbe either a human or a machine.

Therefore, this automation strategy definesthe roles and responsibilities of users in terms of automation instead of the other way around.

First, byautomating everything that can be automated, the user is left with functions that, by definition, thedesigners find hard, expensive, or difficult to automate.

Task allocation is a central challenge in HCI and automation.

Independently of the chosen strategy, some tasks are to be done by the interactive system andsome by the user. The allocation of such tasks is called functional allocation.

A central concern in the design of automation and AI is task sharing.

In all cases, getting the right balance betweenautomation and human control is crucial.

Text entry can also be seen as a task where different subtasks are shared between the human and the computer (Chapter 20).

Text entry is also a good example of tool use (Chapter 19). A text entry method is a tool that allows the user to communicate with someone or something, typically other people or a service, using asynchronous text messages and longer documents.

Text entry can also be seen as dialogue (Chapter 18).

A fundamental goal of interaction is to provide users with tools that allow them to achieve goals that they would otherwise not have been able to achieve.

One goal of interaction is communicating intentions, for example, issuing commands to a computer, selecting graphical elements in image processing software, or entering text.

First, text entry can be seen as the transmission of typed information to a computer.