Many high-hazard industries around the world have explicitly recognized the critical role that human, management and organizational risk factors play in major accidents (Booth and Lee, 1995 and Oien, 2001). An analysis of the main accidents that have taken place throughout history shows that these events cannot be explained by random equipment failures alone, but also by a combination of human and organizational factors. Some of these accidents from the late 1970s and the 1980s include: Three Mile Island accident in 1979 (Kondo, 1996, Le Bot, 2004 and Maddox and Muto, 1999); Bhopal gas tragedy on 3 December 1984 (Shrivastava, 1994); Space Shuttle Challenger disaster on 28 January 1986 (Winsor, 1988 and Winsor, 1989); the Chernobyl disaster on 26 April 1986 (Medvedev, 1991, Meshkati, 2007, Misumi et al., 1999 and Stanton, 1996); and the explosion onboard the Piper Alpha oil platform in 1988 (Moore and Bea, 1993 and Pate-Cornell, 1993).
That is why the incorporation of organizational factors into risk management, measurement and control models took on such importance in the 1990s. For example, PSA, Probabilistic Safety Assessment, is a methodology for quantifying risk in industrial domains. Traditional PSA (Rasmussen, 1997 and Rasmussen, 1975) does not explicitly account for the influence of organizational factors on accident risk. After conducting an analysis of the main accidents, however, the incorporation of organizational factors into PSA has been addressed by various researchers. Embrey (1992) developed a model based on Bayesian Network (BN) for the inclusion of organizational factors in PSA as applied to the rail transportation sector. (Davoudian et al., 1994a and Davoudian et al., 1994b) developed an approach, applicable to Nuclear Power Plants (NPPs), called work processes analysis model (WPAM). The WPAM uses a set of twenty organizational factors developed for the Nuclear Regulatory Commission (Jacobs and Haber, 1994). The ASRM (Luxhoj, 2004) utilizes the Human Factors Analysis and Classification System (HFACS). The omega-factor approach is a method that models organizational failures and their influence on NPP safety (Mosleh et al., 1997 and Mosleh and Goldfeiz, 1999). The Socio-Technical Risk Analysis (SoTeRiA) extends the PRA framework to include the effects of organizational factors as the fundamental causes of accidents and incidents. This framework integrates the technical system risk models with the social (safety culture and safety climate) and structural (safety practices) aspects of safety prediction models (Mohaghegh et al., 2009, Mohaghegh and Mosleh, 2009a and Mohaghegh and Mosleh, 2009b). Finally, Léger and Weber (2009) developed a method for risk assessment considering three main aspects on the system resources: technical, human, and organizational; the integration is based on system knowledge structuring and its unified modeling by means of BN.
The findings of accident investigations and risk assessments evidence a growing recognition that the cultural context of work practices may influence safety just as much as technology (Antonsen, 2009 and Goh et al., 2010). The assumed link between culture and safety, epitomized through the concept of safety culture, has been the subject of intense research in recent years (Antonsen, 2009, Guldenmund, 2007, Kettunen et al., 2007 and Mengolini and Debarberis, 2007).
The term “safety culture” was introduced into the nuclear industry by the IAEA’s International Nuclear Safety Advisory Group after the Chernobyl accident to denote the management and organizational factors that are important to safety (INSAG, 1986). But safety culture may not capture all of the management and organizational factors that are important to safe plant operation (Sorensen, 2002). The major problem with most existing safety culture models is that they are not integrated into general models of organization and of organizational culture (Grote and Kunzler, 2000).
Organizational culture is a concept often used to describe shared corporate values that affect and influence members’ attitudes and behaviors. In the literature, no attempt is made to link or integrate safety culture with organizational culture. The goal of this paper, then, is to establish a relationship between these two concepts of safety culture and organizational culture, in order to determine how to improve safety culture by altering organizational aspects.
The methodology used to achieve this aim relies on Probabilistic (Bayesian) Networks (BNs). Currently, BNs are being applied in different research related to safety (Galan et al., 2007, García-Herrero et al., 2012, Li et al., 2012, Mariscal Saldaria et al., 2012 and Zhao et al., 2012). For instance, Zhou et al. (2008) proposed a BN model to establish a probabilistic relational network among causal factors, including safety climate factors and personal experience factors, which exert influences on human safety behavior. McCabe et al. (2008) demonstrated using BNs that the higher the work pressure, the higher the interpersonal conflict. They also showed that low-quality leadership was most strongly associated with work-related health problems and accidents. Martín et al. (2009) used BNs to analyze the factors affecting the performance of tasks that involve a high risk of falls from ladders or from other auxiliary equipment. This enabled them to identify the circumstances that have the greatest bearing on workplace accidents during these activities, such as the adoption of incorrect work postures, the duration of tasks and a worker’s inadequate knowledge of safety regulations.
Focusing on people and organizations, the paper by Ren et al. (2008) aims to contribute to offshore safety assessments by proposing a methodology to model causal relationships with a BN capable of providing graphical inter-relationships and of calculating numerical values for the likelihood of each failure event occurring. Bayesian inference mechanisms also make it possible to monitor how a safety situation changes when information flow travel forwards and backwards within the networks.
In this paper we analyze the relationships between organizational and safety cultures in a nuclear power plant (Santa María de Garoña-Nuclenor S.A., Spain) using Bayesian networks. Section 2 defines the concept of organizational culture and describes the organizational culture questionnaire used in the study, that is, the Organizational Culture Inventory (OCI). Section 3 defines the concept of safety culture and explains the questionnaire used to asses safety culture. The methodology is illustrated in section 4. In order to quantitatively establish the relationship of the model, a survey of every employee at the nuclear power plant was conducted in June of 2007; in section 4.1 data acquisition is explained. The survey consisted of two parts: the first part included 120 questions related to organizational culture, taken from the Organizational Culture Inventory (OCI) developed by Human Synergistics International (Cooke and Lafferty, 1987); and the second part, on safety culture, included 35 questions (written by the authors) based on the five components of safety culture defined by the International Atomic Energy Agency (IAEA). The study used probabilistic Bayesian network models to analyze the influence of organizational cultures on safety culture. In section 4.2 Bayesian network models are briefly described. Section 5 shows the results and establish the probabilistic relationship among organizational culture factors, including the 12 OCI scales that have an influence on safety culture. Finally conclusions are developed in the last section; in summary, this study allows us to identify those steps to take so as to improve the safety culture at a nuclear power plant.
The study presented used probabilistic Bayesian network models to analyze the influence exerted by each of the organizational cultures on safety culture in a NPP.
First, it seems that the constructive styles are those that have the greatest influence on the safety culture results. In contrast, the defensive styles do not, in general, exhibit a clear relationship with safety culture. This does not mean that we should forget the defensive style to improve safety culture; the detailed analysis, made with each norm, and above all the global model carried out in this study shows how defensive styles also contribute to improving safety culture.
The detailed studies of the four constructive cultural norms (humanistic, affiliative, achievement and self-actualizing) reflect the specific actions that serve to enhance the safety culture in the NPP. Thus, in the humanistic culture, we note the following actions: worrying about the needs of others, involving others in the decisions that affect them, resolving conflicts constructively and being supportive of others and rewarding others. The most influential behaviors in the affiliative culture are: collaborating with others, treating others in a friendly and pleasant manner, thinking in terms of satisfying the group, showing concern for people and behaving tactfully. In the achievement culture, adhering to standards of excellence and knowing the company’s activity are vital to improving the SC. Lastly, in the self-actualizing culture, the behaviors that reinforce the SC are resisting conformism, communicating ideas, being open with oneself and enjoying work.
Analyzing the defensive styles even further, we note the existence of four different behaviors. First, the cultural norms that do not correlate: the approval culture, the conventional culture, the power culture and the competitive culture. Second, those that show how specific actions enhance the safety culture, such as the dependent culture. Third include those that are inversely related to safety culture, such as the avoidance culture. And lastly involves those featuring variables that favor and oppose the safety culture, such as the oppositional and perfectionistic culture.
Below are the specified defensive actions that enhance or harm the safety culture in the NPP. In the dependent culture, reviewing decisions with superiors enhances the safety culture. The avoidance culture exhibits an inverse relationship with safety culture, which are realized in actions such as: keeping out of sight when difficult situations arise and never being the one blamed for mistakes. Within the oppositional culture, looking for errors, adopting an impartial and completely objective attitude, and pointing out flaws, help to improve the safety culture; on the other hand, remaining on the sidelines is a type of behavior that does not favor the safety culture. In the perfectionistic culture a behavior that is directly related to the safety cultures is diligence and persistence.
Finally, a global model has been constructed in order to identify the behaviors that play the greatest role in improving SC. This model involves all of the organizational cultural norms and includes the most relevant variables having thus been identified in the detailed studies. These most influential behaviors on SC, classified by cultures, are specified below. Within the humanistic culture are: resolving conflicts constructively, involving others in those decisions that affect them, worrying about the needs of others and being supportive of them. In the affiliative culture the following stand out: collaborating with others, treating others in a friendly and pleasant manner and thinking in terms of satisfying the group. Negative influences in the avoidance culture include: keeping out of sight when difficult situations arise and avoiding being blamed for mistakes. In the oppositional culture, looking for errors, pointing out flaws and not remaining on the sidelines have an exceedingly high influence on SC. Within the achievement culture includes knowing the company’s activity. And lastly, in the self-actualizing culture, communicating ideas.
The principal advances of knowledge made with the approach, developed in the present research, are the identification of the three principal norms and behaviors necessaries to achieve maximum results in safety culture. These behaviors, classified in order of importance, are: looking for errors, not keeping out of sight when difficult situations arise, and resolving conflicts constructively. In addition the model shows others behaviors that also contribute to improve safety culture. Taking steps to improve these behaviors has been identified as paving the way to enhancing safety culture at a NPP.
For future research it would be advisable to compare safety culture and organizational culture in others companies. It would be interesting to know if the organizational cultural norms have the same influence in safety culture in chemical, manufacturing, mining and others industries.
