Applicable stages: requirement, and design.
Personnel needed for the evaluation: Usability experts: 1 Software developers: 0 Users: 2	Usability issues covered: Effectiveness: No Efficiency: No Satisfaction: No
Can be conducted remotely: No	Can obtain quantitative data: No

 Overview

Before designing a system, in order to understand the the users, their tasks, and their working environment, human factors engineers go to representative users's workplace and talk to them, observe them work, and ask them questions, to understand the user characteristics, the work flow, the system features they need, etc. This technique should be used during the requirement or early design stage of software development. This should be the first step of usability work for a project.

Find a group of representative users who will be able to participate in the field study. Make appointments with them for usability engineers to visit them at their working environment and talk to them. The issues to be addressed for such a field study generally include:

• Individual User Characteristics: work experience, educational level, age, previous computer experience, work environment, etc. Identify the user characteristic issues that may affect their use of the system to be developed and address these issues during the field study.
• Task Analysis: the users' overall goals, their current approach, the users' model of the task, their information needs, and how they deal with exceptional circumstances or emergencies. A typical outcome of a task analysis includes:
  • a list of all the things users want to accomplish with the system,
  • all the information they will need to achieve these goals,
  • the steps that need to be performed and the interdependencies between these steps,
  • all the various outcomes and reports that need to be produced
  • the criteria used to determine the quality and acceptability of these resutls
  • the communication needs of the users as they exchange information with others while performing the task or preparing to do so.
  These information should be collected by both talking to the users and observing some concrete examples of their work. Also users should be asked to describe exceptions from their normal work flow.
• Functional Analysis: focus on the goals that the users want to achieve but not necessarily keeping the ways how the users are currently doing things. Try to provide the users with a "power tool" that will let them do their job more easily. Functional analysis should be coordinated with a task analysis so that the new ways for accomplishing the tasks will be as consistent as possible with the old ways.
• The Evolution of the User: Using the system changes the users, and as they change they will use the system in new ways. Study how users have changed in the past through the use of similar systems. A typical change is that users become experts after some time and want interaction shortcuts (also called accelerators).

1. J. Nielsen "Usability Engineering" pp.73-79, Academic Press, 1993.