8
Sensemaking in Safety Critical and Complex Situations
FIGURE 1.10 Example of putting data into context.
Early designs of displays also revealed numerous repeats of the same information.
The task analysis provides insight into rationalizing the required data and information, offering a dramatic reduction in the total number of displays. Task analysis has
typically reduced 12 current screens used to achieve a simple processing task and
consolidate the required data onto one screen.
A goal of the task analysis is to consolidate data and turn data into information, as
seen in the example presented in F igure 1.10.
The left side shows the usual format of data on display without any context. It
relies on the operator’s understanding and ability to remember 1,000s of data points,
what their working range is, and then put the data in context. Short-term memory
issues compromised situation awareness leading to human error and missed warnings. Having the reference range next to the value is useful, but not very practical as
it requires a lot of cognitive work to make the comparison of data to the range specified. Using “ reveal information” when hovering the cursor over the value is one way
to achieve this goal but again not very practical. A simple graphical indicator can put
the data into context immediately for the operator. We follow this practice by adding
the number when the data is o ff-normal.
THE POWER OF THE COMPUTER ALLOWS AN
INCREASE IN SCOPE OF CONTROL
The operator usually has a formal desk known as a console with screens to show each
of the operating units. Unfortunately, with more and more units added, there comes
the point when more screens are not practical. It is not unusual to see a console with
12–16 screens, and the operator tries to build an overview of each of the units under
their scope of control.
There are some concerns and challenges that must be addressed:
• How many units can a single operator manage?
• What happens if more than one of the plant units is in a disturbance at the
same time? Do they prioritize one and ignore the other.
• Does the operator have sufficient time to respond to alarms before the consequences happens?
Sensemaking in Safety Critical and Complex Situations
FIGURE 1.10 Example of putting data into context.
Early designs of displays also revealed numerous repeats of the same information.
The task analysis provides insight into rationalizing the required data and information, offering a dramatic reduction in the total number of displays. Task analysis has
typically reduced 12 current screens used to achieve a simple processing task and
consolidate the required data onto one screen.
A goal of the task analysis is to consolidate data and turn data into information, as
seen in the example presented in F igure 1.10.
The left side shows the usual format of data on display without any context. It
relies on the operator’s understanding and ability to remember 1,000s of data points,
what their working range is, and then put the data in context. Short-term memory
issues compromised situation awareness leading to human error and missed warnings. Having the reference range next to the value is useful, but not very practical as
it requires a lot of cognitive work to make the comparison of data to the range specified. Using “ reveal information” when hovering the cursor over the value is one way
to achieve this goal but again not very practical. A simple graphical indicator can put
the data into context immediately for the operator. We follow this practice by adding
the number when the data is o ff-normal.
THE POWER OF THE COMPUTER ALLOWS AN
INCREASE IN SCOPE OF CONTROL
The operator usually has a formal desk known as a console with screens to show each
of the operating units. Unfortunately, with more and more units added, there comes
the point when more screens are not practical. It is not unusual to see a console with
12–16 screens, and the operator tries to build an overview of each of the units under
their scope of control.
There are some concerns and challenges that must be addressed:
• How many units can a single operator manage?
• What happens if more than one of the plant units is in a disturbance at the
same time? Do they prioritize one and ignore the other.
• Does the operator have sufficient time to respond to alarms before the consequences happens?