Appendix D - Events and Casual Factor Analysis

(Cause and Effects [Walk-through] Task Analysis)

Cause and Effects (Walk-through) Task Analysis is a method in which personnel conduct a

step-by-step reenactment of their actions for the observer without carrying out the actual function. If

appropriate, it may be possible to use a simulator for performing the walk-through rather than the actual

work location.

Objectives include:

Determining how a task was really performed

Identifying problems in human-factors design, discrepancies in procedural steps, training,

etc.

Preconditions are that participants must be the people who actually do the task.

Steps in Cause and Effects Task Analysis are as follows:

Obtain preliminary information so you know what the person was doing when the problem or

inappropriate action occurred.

Decide on a task of interest.

Obtain necessary background information:

Obtain relevant procedures

Obtain system drawings, block diagrams, piping and instrumentation diagrams, etc.

Interview personnel who have performed the task (but not those who will be observed) to

obtain understanding of how the task should be performed.

Produce a guide outlining how the task will be carried out. A procedure with key items

underlined is the easiest way of doing this. The guide should indicate steps in performing task and

key controls and displays so that:

You will know what to look for

You will be able to record actions more easily.

Thoroughly familiarize yourself with the guide and decide exactly what information you are going

to record and how you will record it.

You may want to check off each step and controls or displays used as they occur. Discrepancies

and problems may be noted in the margin or in a space provided for comments, adjacent to the

step.

Select personnel who normally perform the task. If the task is performed by a crew, crew

members should play the same role they fulfill when carrying out the task.

Observe personnel walking through the task and record their actions and use of displays and

controls. Note discrepancies and problem areas.

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