PATTERN 2: MULTIPLE REPRESENTATIONS OF INFORMATION

Essence of the Pattern:

This pattern is concerned with how people make use of multiple representations of information when performing their work. This is evident particularly in critical real-time work such as takes place in control rooms. Here, the alternative representations of the data provide different views which may be particulary suitable for certain tasks. In the cases documented the different views are utilised for different tasks such as visualising the here-and-now situation versus planning activities, or taking a global versus a local perspective of a problem. When these various representations are communal objects shared by a group of workers this allows for the activities to be collaboratively achieved through group as well as individual reconciliation. This also allows some task separation and redundancy in the system as the same information may be available in different views to a number of workers.

Why Useful?

Providing multiple representations of information allows for complex activities to be broken down into more manageable tasks. Different views provide for supporting different aspects of the activity. When these are available to a small, collocated group this allows for different members to work on different parts of the activity simultaneously and to collaborate in solving more complex tasks. The redundancy in the information and also the group can be useful in ensuring the dependability of the system.

Where Used?

This pattern has been documented in two settings so far. The focus is on various representations of a problem situation. These may offer global versus local views or allow for assessing the here and now versus planning activities. The focus is on how these are utilised by small groups of collocated workers particularly in control room settings.

This pattern is illustrated with vignettes from the following field work:

* AmbulanceControlFirstExample: How ambulance controllers refer to different status displays in order to make decisions on which resource to allocate to an incoming call, and to determine the load on each resource.

* AirTrafficControlSecondExample: How air traffic controllers make use of radar displays together with the paper flight strips in order to manage the flights through the sector of air space they are responsible for.

* HospitalSecondExample: How hospital workers make use of different representations of bed availability.

Dependability Implications?

In a situation, particularly involving a complex, real-time, dynamic task such as handled in a control room it is useful to employ multiple, different, representations of that unfolding task which may be both textual and visual. These can be designed to focus on different aspects of the activity or to present them in different ways. This provides a resource for managing the different tasks involved in achieving the activity and builds necessary redundancy into the system making it more likely that failures will be spotted early or avoided. When these are made available to a small, collocated group as in the documented settings this allows for the tasks to be solved collaboratively and builds in an extra level of redundancy in the personnel.