Task Analysis

Question 1

task analysis

Answer 1

used to understand and represent human and system performance in a particular task or scenario.
Helps us identify and understand:
The things people do
The things people act on
The things people need to know. One of the most commonly used group of techniques in HF (if not the most common)

Question 2

When can task analysis techniques be used?

Answer 2

can be used during the design of systems, OR to evaluate existing systems or processes

Question 3

Task anaylsis involves:

Answer 3

identifying tasks
collecting task data
analyzing the data so that tasks are understood
producing a documented representation of the analyzed tasks

Question 4

What do task analyses do?

Answer 4

Typical task analysis techniques break down tasks or scenarios into the required individual task steps, in terms of the required human-machine and human-human interactions

Question 5

Hierachical Task Analysis

Answer 5

involves breaking down the task under analysis into a hierarchy of goals, operations and plans
Tasks are broken down into hierarchical set of tasks, sub tasks and plans
HTA has been widely used in a number of domains including (but not limited to):
process control and power generation industries, military applications, aviation, training, error and risk analysis, identification and assessment of team skills

Question 6

goals

Answer 6

The unobservable task goals associated with the task in question

Question 7

operations

Answer 7

The observable behaviors or activities that the operator has to perform in order to accomplish the goal of the task in question

Question 8

plans

Answer 8

The unobservable decisions and planning made on behalf of the operator

Question 9

Step 1 in an HTA:

Answer 9

Determine the overall goal of the task
The overall task goal of the task under analysis should first be specified at the top of the hierarchy i.e., “boil kettle”

Question 10

Step 2 in an HTA:

Answer 10

determine task subgoals

Question 11

to determine task subgoals

Answer 11

Break the overall goal down into four or five meaningful sub-goals, which together make up the overall goal
In a HTA analysis of a Ford in-car radio the task, “listen to in car entertainment”, was broken down into the following sub-goals:
Check unit status
Press on/off button
Listen to the radio
Listen to cassette
Adjust audio preferences

Question 12

Step 3 in an HTA:

Answer 12

Sub-goal decomposition

Question 13

Sub-goal decompostion includes:

Answer 13

The sub-goals identified in step two should then be broken down into further sub-goals and operations, according to the task
This process should go on until an appropriate sub-goal is reached
The bottom level of any branch in a HTA will always be an operation
While everything above an operation specifies goals, operations actually say what needs to be done
Operations are actions to be made by the operator
Underneath the sub-goals, the analyst basically enters what needs to be done to achieve the sub-goal

Question 14

Step 4 in an HTA:

Answer 14

Plans analysis

Question 15

Plans analysis includes:

Answer 15

Once all of the sub-goals have been fully described, the plans need to be added.
Plans dictate how the goals are achieved.
A simple plan would say, Do 1, then 2, and then 3.
Once the plan is completed, the operator returns to the super-ordinate level.
Plans do not have to be linear and can come in any form such as Do 1, Or 2 And 3.
Once the goals, sub-goals, operations and plans are exhausted, a complete diagram made up of these four aspects of the task makes up an HTA. If required, this can be tabulated.

Question 16

Advantages of HTA

Answer 16

HTA is the starting point for numerous human factors techniques
Easy to learn and implement
Requires minimal training
Usually quick to use
Used extensively in a wide range of contexts
Gives great insight into the task under analysis
Excellent technique to use when requiring a task description for further analysis
Can depict everything that needs to be done in order to complete the task in question
Adaptable to a wide range of purposes
Tasks can be analyzed to any required level of detail, depending on the purpose

Question 17

Disadvantages of HTA

Answer 17

Provides mainly descriptive information rather than analytical information
Contains little that can be useddirectlyto provide design solutions
Does not cater for thecognitivecomponents of a task
Can be time consuming and laborious for the more complex and larger tasks
Requires handling by an analyst well trained in a variety of methods of data collection and in relevant human factors principles
Requires time in proportion to the complexity of the task and the depth of the analysis
Still no good software application to help out with this technique

Question 18

Cognitive Task Analysis

Answer 18

“Cognitive task analysis methods focus on describing and representing the cognitive elements that underlie goal generation, decision making, judgments, etc. Although cognitive task analyses often begin with high-level descriptions of the task based on observations or initial interviews,the bulk of the data collection occurs via in-depth interviews with subject matter experts. These interviews focus on gaining information about the cognitive strategies used to accomplish the task including situation assessment strategies, identification and interpretation of critical cues, metacognitive strategies, important perceptual distinctions, etc. One strength of these methods is that they aid experts in articulating knowledge that is generally difficult to verbalize

Question 19

What CTA does

Answer 19

Breaks down the components of the task in terms of the cognitive ability required during each step
May examine the perceptual ability or motor ability requirements as well

Question 20

CTA, although powerful, requires:

Answer 20

An understanding of cognition
An expert-level understanding of the task (either your own or by interviewing a subject matter expert)
Think aloud protocol can be helpful here!