Task Analysis

by Janette B. Bradley
axsWave Software, Inc.™

1. Task Oriented User Requirements and Program Design: An Approach to Writing Programming Objectives And Specifications. Authors are Frederick J. Terrio & James J. Vreeland. August 1980.
2. A Guide to Software Usability. Author is Kathleen M. Snyder. 1991

Identify the user

• Visit participating location. Talk with intended users. Attempt to identify various types of users and what they expect from a system.
  
• Observe users doing work. Focus on the various types of people performing the work of interest.
  
• Survey users with questionnaires, interviews or phone call to better understand who might be using the new system.
  
• Create a focus group and invite users to talk about the type of users who might use the system.

Classify users

• As information is collected about users, classify them according to the proportion of the total user population each class represents. Classify users according to their actual background rather than traditional job description categories.

Identify special characteristics

• For each user class, identify important characteristics that could influence design decisions. Think of these characteristics as user trace that could constrain the use of a system. The system should be designed to accommodate these constraints. Some characteristic to consider are: educational level, reading level, skills and training, computer literacy, domain knowledge.

Understand the user environment

• Describe the environment in which the system is to be used. Identify characteristics of the environment that could impact design. Issues to consider are environmental factors, work factors and user factors. Examples of environmental factors include space, light, acoustics, etc. Work factors include system currently in use, company structure and organization, amount and type of work required of the user. User factors include amount of system usage, intensity of usage, etc.

Defining task requirements

• A task is a sequence of responses to situations and conditions that lead from a starting state to a goal state. A task analysis is an ordered sequence of tasks and subtasks, which identifies: the performer or user; the action, activities or operations; the environment; the starting state; the goal state; the requirements to complete a task such as hardware, software or information. Task analysis moves the emphasis from the function provided to how the user will use the function.
  
• Knowing what tasks the user wants or needs to accomplish is essential to building an effective systems. Defining these tasks form the basis for determining the functions that need to be included in a system in order to meet requirements. When tasks are identified, it is also important to understand how users complete, or expect to complete, tasks. These expectations can be thought of as the user model of how the system should work. Once user expectations are understood, they can be used as the basis for system design.
  
• Communicating directly with potential users is the best way to identify the tasks they want to accomplish and the way they expect to accomplish them. This can be done in either a lab setting or in the user's working environment. Contact and communications must be systematically structured to ensure that valid data is collected.
  
• Remember that the reason you are identifying tasks is to acquire an understanding of the problems users face so that a solution can be designed to solve their problems. An effective way to collect information about tasks is to try to identify what the user does in a normal work day. This procedure is contrasted to the approach where users are merely asked what functions they want in a system or what individual tasks are associated with the job they perform. Although this latter approach is task-oriented, task information collected in this way lacks context. This leaves designers in a situation where they must envision how the tasks fit together in a normal work environment rather than having accurate information available from users. Identifying typical work load scenarios helps the designer acquire a better understanding of what different users require.

Questions to ask:

• What tasks are the users currently performing?
  
• What is the sequence of steps the users take to perform a task, and what is the relationship between the steps?
  
• What do the users think would make the system usable?
  
• Who does the user interact with to complete each task?
  
• What is the relative importance of each task?
  
• What are the criteria for a successful task execution?
  
• What supporting equipment or aids do the users need?
  
• What are the most likely and most significant errors the user could make?
  
• How often do users perform the tasks?
  
• How do the users learn the task?
  
• What are the time constraints on the task?
  
• What happens when things go wrong?
  
• What hardware, software and other systems are users currently using and what equipment must your system complement?
  
• What do users think would demonstrate that your system is the best available?

Writing the Task Analysis

• In writing the task analysis, you do not anticipate system function. You describe the tasks in terms of the job that they will accomplish by using the system, not in terms of how users will use the system. For example, user requirements do not state that users need a facility to do a particular task. Instead the requirements state some task that the user needs to do or needs to do more efficiently or effectively. If the completion of a single task requires several steps, present a complete scenario of all the steps or subtasks that are involved. During this process, make sure that all requirements that will affect the user interface to the system reflect some task.
  
• Each generalized task description consists of a list of subtasks. To tailor a task description, you use the subtasks as an outline. You add subtasks to, subtract subtasks from, or modify subtasks of each task description, depending on the facilities and options you intend to offer. The process is an iterative one. After an initial pass of the task analysis is complete, you decide which task will be supported by the system. Keep in mind that your knowledge of the system should not anticipate how the product's functions or interface will be designed to meet the user requirements.

Feel free to contact me with questions or to talk about how the axsWave Software team can help you with your Web site:

Janette B. Bradley (janette@metronet.com)