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Article Excerpt
Introduction
In many high-reliability organizations, overall systems operations are the responsibility of a small crew that controls multiple systems and makes decisions concerning system functioning. These control crews are teams of highly trained individuals who work and train together to monitor system interfaces and keep systems at equilibrium (Waller and Jehn 2000). Control crews are particularly prevalent in aviation, naval operations, petroleum and chemical refining, nuclear power, and other environments in which reliability of performance is crucial. These crews are often referred to as the "brains" of the complex systems they manage, because control crews are responsible for interpreting information from multiple systems and making accurate decisions during abnormal, time-pressured, high-workload situations.
Existing literature concerning control crews and their organizations suggests two central themes regarding control crew performance. First, because control crews' actions during abnormal situations are so critical in high-reliability contexts, much of the research on control crews and the training they receive focuses on their actions during abnormal, high-workload situations (see Waller 1999, Weick 1993), and includes the actions taken by crews and organizations to manage and learn from crises (Roberts 1993, Weick and Sutcliffe 2001). Work in this area focuses on the idea that successful crews must "think on their feet and do the 'right thing' in novel situations" (Weick and Roberts 1993, p. 358).
Second, while crew behaviors during nonroutine situations are clearly critical to crew and organization performance, other work in this area suggests that what crews do during lower-workload levels significantly impacts their overall performance. Specifically, this work suggests that higher-performing control crews prepare for possible abnormal situations by planning for such situations during lower-workload periods (Huey and Wickens 1993, Orasanu 1993, Pepitone et al. 1988, Stout et al. 1999).
These two central themes about control crew actions motivate our research regarding the timing and content of control crew actions. Taken together, these themes suggest that the pattern of crew behaviors over time and across variable workload conditions might play an important role in overall crew performance. The study reported here examines behavioral differences between lower- and higher-performing control crews in an effort to help explain why some crews are able to perform well in dynamic workload environments while other crews are not. Specifically, the study focuses on differences in key crew behaviors as suggested by existing work, and follows these behaviors across the various workload conditions associated with monitoring (low-workload), routine (moderate-workload), and nonroutine (high-workload) situations. Our general research question is: Do the two suggested factors of control crew performance--how crews behave when a crisis occurs versus how crews behave when no crisis exists--play equally important roles in differentiating higher- from lower-performing crews? After reviewing pertinent literature, we present hypotheses and describe a study of 14 nuclear power plant control room crews. This paper closes with a discussion of implications for future research and practitioners.
Literature Review and Hypotheses
Control crews face dynamic workloads that vary from monitoring (low-workload), routine (moderate-workload), and nonroutine (high-workload) situations. Monitoring situations entail vigilance because each crew member "routinely scans one or more sources to detect the presence of a previously specified signal or a change in the value of a particular parameter" (Huey and Wickens 1993, p. 72); thus, during monitoring situations the systems controlled by the crew are at stasis (Hollenbeck et al. 1995). During routine operations situations, crews respond to systems information by engaging in well-trained standard operating procedures to maintain or improve the functioning of the systems. Finally, during nonroutine situations, crews act to manage unexpected and unfamiliar problems that could result in system failure if left unchecked (Kantowitz and Casper 1988, Rouse 1979).
Research on control crews and teams inform our hypothesis development and suggest two key areas of control crew behavior to examine: adaptive crew behaviors and shared mental model development. The first area of work to be discussed suggests that three adaptive behaviors affect crew performance: information collection, task prioritization, and task distribution behaviors.
Adaptive Crew Behaviors
Information collection behaviors have been shown to be extremely important to crew performance under high-workload conditions (Kawano et al. 1991, Stanton 1996). Information collection involves collecting and recognizing information concerning the need for action (Waller 1999). Work on situation awareness suggests that information collection plays an integral role in both individual and team performance, because operators of complex systems collect information about system cues in their environments, comprehend that information in terms of the current situation and their past experience, and use that information to project future situation problems and dynamics (Endsley and Garland 2000, p. 5). At the team level of analysis, the collection of information by team members plays a critical role in increasing the team's awareness of the situation (Prince and Salas 2000, p. 326).
In high-workload settings, new information about changes in system status or about nonroutine problems occurring is collected by crew members scanning the environment, and is often subsequently transferred to other crew members through horizontal communication. For example, in a study of flight crews, Waller (1999) found that higher-performing crews engage in significantly more information collection behavior than do lower-performing crews. Particularly during complex nonroutine situations, the collection of new information might play a critical role in crew success. Conversely, other work suggests that because workloads and perceived uncertainty increase during nonroutine problems, lower-performing crews might adopt centralized structures (Argote et al. 1989) that constrain the flexibility of individuals' roles and reduce the opportunity of individual crew members to notice and collect information, thus reducing overall crew performance. These centralized structures might be adopted due to a threat-rigidity response (Staw et al. 1981), because lower performers perceive higher levels of workloads and more uncertainty than higher-performing crews. Thus, we hypothesize:
HYPOTHESIS 1. During nonroutine situations, higher-performing control crews will engage in more information collection than will lower-performing crews.
Second, crew task prioritization behaviors are necessary to allow crews to plan for and prioritize tasks during low-workload situations, and to adapt operations from task prioritization schemes for lower workloads to task prioritization schemes for high-workload conditions that might be brought about by nonroutine situations (Helmreich and Foushee 1993). Upon recognition of a nonroutine situation, high-performing crews might deprioritize some tasks and focus instead on tasks critical to managing the situation, whereas low-performing crews might recognize the situation but adhere to the original prioritization scheme. Although she found no significant difference between low- and high-performing crews regarding the overall amount of this behavior, Waller (1999) found that higher-performing crews are more likely than other crews to reprioritize tasks during nonroutine situations. We therefore hypothesize:
HYPOTHESIS 2. During nonroutine situations, higher-performing crews will engage in more task prioritization than will lower-performing crews.
Finally, task distribution refers to the effective allocation of tasks, and is "crucial in high reliability systems" (Stanton 1996, p. 117). The...
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