<Li> Task analysis: A process with roots in activity theory, task analysis is a way of systematically describing human interaction with a system or process to understand how to match the demands of the system or process to human capabilities . The complexity of this process is generally proportional to the complexity of the task being analyzed, and so can vary in cost and time involvement . It is a qualitative and observational process . Best used early in the design process . </Li> <Li> Think aloud protocol: Also known as "concurrent verbal protocol", this is the process of asking a user to execute a series of tasks or use technology, while continuously verbalizing their thoughts so that a researcher can gain insights as to the users' analytical process . Can be useful for finding design flaws that do not affect task performance, but may have a negative cognitive affect on the user . Also useful for utilizing experts to better understand procedural knowledge of the task in question . Less expensive than focus groups, but tends to be more specific and subjective . </Li> <Li> User analysis: This process is based around designing for the attributes of the intended user or operator, establishing the characteristics that define them, creating a persona for the user . Best done at the outset of the design process, a user analysis will attempt to predict the most common users, and the characteristics that they would be assumed to have in common . This can be problematic if the design concept does not match the actual user, or if the identified are too vague to make clear design decisions from . This process is, however, usually quite inexpensive, and commonly used . </Li> <Li> "Wizard of Oz": This is a comparatively uncommon technique but has seen some use in mobile devices . Based upon the Wizard of Oz experiment, this technique involves an operator who remotely controls the operation of a device to imitate the response of an actual computer program . It has the advantage of producing a highly changeable set of reactions, but can be quite costly and difficult to undertake . </Li>

Which of these is a key concern for the field known as ergonomics or human factors