Based on the results of the study, optimism among nurses and nurse aids are higher than the average. Optimism was reported in lower levels in other professions (
19-
21). Higher optimism can be attributed to the providing health services as the type of work. Nurses, as the most important component of care system and patient safety, learn in their job that hope for the future and positivism can greatly contribute to faster recovery of their patients. In fact, today’s organizations need optimism to create job satisfaction and job enrichment (
22). Based on the results of this study and in line with other research (
11), men had higher optimism than women. It seems that female nurses, due to having more feelings and emotions involved in these tasks, are more affected by their occupational environment than male nurses. Optimism in its general concept can improve occupational health and safety and the patient’s safety. Based on studies of other researchers optimism, as an important factor of psychological capital (
23), led to increase in self-esteem (
24), had positive impact on resiliency and flexibility of people (19), indirectly affect the safety climate (
25), is associated with mental health (
26), has a positive effect on job satisfaction and organizational commitment (
27), is correlated with organizational successfulness (
28), leading to better fitting of individuals with their workplace (
29), rises the organizational happiness (
20), and eventually affect unsafe behaviors in workplace (
30).
On the other hand, optimism reduces job burnout (
31) and reduces job stress indirectly (
32). Hanssen believes that optimism is an important variable for predicting mental health and social adaptation of people (
33). Respects to the advantages enumerated above and presence of optimism more than average score in nursing profession, there is a great asset available for hospital managers to use the appropriate leadership style to enhance productivity and efficiency of their organizations (
34). Optimism is a type of thinking pattern not a permanent part of the human character. People can learn to change their thinking pattern (
35). Based on this fact we can promote optimism among people through educational programs (
36). Despite the benefits of optimism, sometimes occupied people are having optimistic bias (
37). Considering the negative relationship between optimism and occupational accidents (
Table 3), nurses and nurse aids experienced optimism bias. “Nothing badly would happen to me compared with other partners” is the keyword of optimism bias. It evokes the crucial concept in occupational health and safety. Lack of experience in case of an accident increases optimism bias. Furthermore, when people feel they have high control on their work, optimism bias would appear. Bias results in inadequate attention to safety considerations and ultimately the unsafe behavior and accident. The reports of risks and errors would also face a reduction. Due to the visibility of optimism bias in the present study, it is recommended that positive imagination about optimism should not lead to neglecting the bias. Although not necessarily, optimistic people do not show bias, however, these two concepts are related and should be studied and planned together in management issues. Another important variable in this study was “post-task behaviors or organizational citizenship behavior”. According to the results, the nurses were higher than average. In other words, nurses and nursing assistances during the defined tasks usually do post-task behaviors that help to improve effectiveness of organization’s services and on the other hand, have a positive impact on coworkers’ performance. Organizational citizenship behavior, like optimism, is improvable through intervention programs (
34). Based on the results of other studies, organizational citizenship behavior can lead to positive effects in the workplace (
38,
39). Considering the outcome of this study and in line with the results of other researches, Optimists do better OCB in the organization (
22,
23,
40). For example, optimists are better involved in teamwork in in hospitals, help more to others in carrying out the responsibilities, report deficiencies and errors more, and follow safety procedures and instructions more (
19,
41). Since the manner and style of management (
34), good communication in the workplace (
42), organizational spirituality (
43), occupational ethics (
44), sense of organization belonging (
40), and perceptions of organizational justice (
45) are in relationship with organizational citizenship behavior, it seems that the definition of training programs to promote these factors as well as management commitment to better communication with staff can lead to improved organizational citizenship behavior. The relationship between occupational accidents and OCB was not established in this study. However, other researchers reported significant correlation between organizational citizenship behavior and accidents (
46,
47). The complexity and diversity of the responsibilities of nurses and huge amounts of labors can be mentioned as reasons for this difference. However, strengthen organizational citizenship behaviors through the promotion of organizational ethics and spirituality can lead to better performance, higher quality of working life (
48), and risk management (
25). In addition, according to the relationship between occupational accidents and the level of education and working shifts in this study, the more bias is expected for nurses with higher educational status. Besides, day working employees, due to the higher workload in their working hours are involved in more accidents. Therefore, it is suggested that day working nurses with a bachelor degree level or higher be considered while implementing intervention programs then other people.