STRATEGIES AND PROGRAMS FOR MANAGING STRESS IN WORK SETTINGS

Abstract

In this paper, the term stress is firstly defined. The economic consequences of stress are also presented. Then, the factors within the work environment and the factors outside the work environment that may cause stress are described. In particular, the individual differences that influence our inclination to stressors and, also, how to manage them efficiently are examined. In addition, the strategies and programs developed in organizations to assist their employees to more easily control stress are discussed extensively. [PUBLICATION ABSTRACT]

Headnote

In this paper, the term stress is firstly defined. The economic consequences of stress are also presented. Then, the factors within the work environment and the factors outside the work environment that may cause stress are described. In particular, the individual differences that influence our inclination to stressors and, also, how to manage them efficiently are examined. In addition, the strategies and programs developed in organizations to assist their employees to more easily control stress are discussed extensively.

1. INTRODUCTION

The word "stress" is one of the most frequently used words today. We live in a fast developing world which requires constant adaptation. Technology is changing, so are social habits, values, social structures, and people. Everybody has to cope with those changes, not only individuals, but organizations and governments as well (Pettinger, 2002; McLean, 1980; Moss Leonard, 1981). The pace of life is getting quicker, too. What was new yesterday, is already old today. A lot of people are aware of the positive values of those changes, but very few think of the negative consequences that may ensue.

According to certain estimates, humankind loses 100 million workdays every year due to the aftermath of stress. More importantly, 50 to 75 % of today's diseases are related to stress. The European Agency for Health and Safety at Work states that stress within organizations is the second most frequent problem and affects as many as 28 % of employees (EAHSW, 2003; EAHSW, 2004).

Loss of health due to stress constitutes neither the biggest nor the only cost in companies. Mistakes and/or false decisions, which employees make under the effect of stress, are even more costly than loss of health. Therefore, it is necessary to think carefully about what to do to prevent stress among employees. In order to solve this problem, various stress management strategies and programs can be developed in the company.

2. DEFINITION OF STRESS

The term "stress" is frequently used in everyday life. Hearing the word stress, makes us first think of something unpleasant, something menacing and beyond our control. However, stress, a factor which has helped people to survive for millenia; today is now considered as enemy number one. To it one has even ascribed the causes of many accidents, diseases, early deaths, suicides, disatisfactions and tensions. In addition, it is difficult to calculate the losses it causes to the economy (Schmidt, 2001).

Nobody is completely imune to stress. It can affect anybody, since it is an important and vital part of our lives. Stress occurs as an inevitable consequence of our relations with our constantly changing environment we have to which we have to adopt (Looker, Gregson, 1993).

The word stress comes from the Anglosaxon world and was first applied in physics for designating mechanical force. It denotes the exterior pressure, tension, load upon an object (Newhouse, 2000). The term stress was first introduced into medicine by Hans Selye in 1949 (1976, 1986). According to his definition stress is a way of physically adaptating to new circumstances or a reply to the irritations that disturb the individual balance (Luban, Pozza, 1994).

Ivanchevich and Matteson (1993) define stress simply as "an interaction of the individual to his or her environment". They also define this term in detail as: "adopted response of a person as a reflection of their diversity and/or psychological processes to activities, states, or events in the environment creating exaggerated psychological and physical needs."

Greenberg and Baron (2000) define stress as "a complex pattern of emotional states, physiological reactions and related thoughts in response to external demands". They refer to the demands emanating from the environment as stressors. Examples of stressors are: the demands of work assignments, interpersonal relations between co-workers, one's relations with one's spouse and children, and social obligations. The third term, strain connected to stress and stressors, according to these authors, refers to the accumulated effects of stress expressed as deviations from normal patterns of behaviour or activity and thus constituting a consequence to the exposure to stressful events.

3. SOURCES OF STRESS

We have already defined stress as the consequence of interaction between the individual and the environment. In this section, attention will be given to the stressors in the environment. First, the factors relating to organisations or jobs, and the factors relating to other aspects of individuals' lives shall be described In addition, the individual differences that influence human responses to stressors, and how to manage them successfully will be examined.

3.1. Work-related causes of stress

Work settings can be very stressful for employees. Some jobs and organizations expose individuals to high levels of stress, whereas others involve much less stress. In work settings various factors may cause employees stress such as type of job, role conflict, responsibility for other employees, conflict between work and private life.

Type of job. Some jobs, such as those of firefighter, senior executive and surgeon, expose workers to high levels of stress. Other jobs, such as those of accountant and actuary, are far less stressful. Surveys show that some jobs are much more stressful than others. They compare people in hundreds of occupations according to a variety of criteria, including overtime, quotas, deadlines, competitiveness, physical demands, environmental conditions, hazards encountered, initiative required, stamina required, win-loss situations, and working in the public eye (Lyness, Thompson, 1997; Cooper et all, 2001). Among the 250 most stressful jobs are those of: president of the country, firefighter, senior executive, surgeon, air traffic controller, public relations executive, stockbroker, pilot, architect, lawyer, physician etc.

Conflict between work and private life. In a modern, technology-based and innovative society, as a rule, both spouses in families with children are employed. The result is a constant juggling of work and family resposibilities. Due to his/her doubts arising between the responsibility to work and family, the employee is susceptible to another widely recognized cause of stress called "role conflict". This conflict occurs as the consequence of incompatibility between the expectations of spouses and employers. Such conflicts between family and work can be lessened by high levels of social support in work settings.

Role conflict in work settings. Employees are more successful at work if they know what is expected of them and if their various roles in organizations are not in mutual conflict. Role conflict in work settings occurs when an individual has to take several different and unconsistant demands into account. If s/he meets one demand, it is impossible to fullfil another one as well (Brewer, 1999; Ross, Altmaier, 2000).

Role ambiguity. Even if an employee can avoid the stress associated with role conflict, s/he still may encounter the stress associated with role ambiguity. This occurs when the individual experiences uncertainty with regard to actions s/he should undertake to meet the requirements of his or her job. For example, John has been promoted to a more demanding job. Since he is not sure what exactly is expected of him, he tries to obtain as much information as possible. So, John faced stress emanating from the role ambiguity when he accepted the new job (Markham, 1995).

Role overload. When the phrase "work-related stress" is mentioned, we usually think of employees working a lot and even more than they can handle. Such images relate to overload, which can take two different forms. Quantitative overload occurs when individuals are asked to do more work than they can complete in a specific period of time. In contrast, qualitative overload refers to employees' beliefs that they lack the required skills or abilities to perform a given job. Both types of overload are unpleasant and both can lead to high levels of stress (McLean, 1980).

Responsibility for others. In general, people who are responsible for others, that is, people who must motivate, reward, punish and communicate with others, experience higher levels of stress and its accompanying physical symptoms than those who handle other organizational functions (McLean, 1980). Responsibility for others is a heavy burden that all executives and managers have to bear. They may feel somewhat happier if they can expect self-motivation of coworkers (Udovièiè, 2004).

Organizational factors. The organisation in which employees carry out their work can also cause stress. Four characteristics thereof may be considered as stress inducers: 1. organizational level, 2. organizational complexity, 3. organizational changes and 4. organizational border roles.

Managers at the top organizational level have to cope with role conflict, resposibility for others, role ambiguity and role overload. They also have more time restrictions and thus can pay (too) little attention to each of their activities. Employees at the lower levels can be exposed to stress due to either the excessive or scanty load of the role. Or, they are faced with role conflict emanating from the controversial requirements of superiors as well from their lack of certain resources.

In regard to organisational complexity, many rules and demands as well as complex nets in large organizations can be stressful to employees. Role overload is quite often present in such work settings, too. Stress can be connected with organisational changes, as well. For example, a new information system is introduced into the organization. The employees may feel stress due to the necessary adaptation of their work to the new information system. The organisational border role can also be a source of stress in the organization. On the one hand the employees must consider the demands of their customers, while on the other hand they must simultanuously accomplish the requirements of their own organization.

Mobbing and workplace violence. Mobbing in the workplace constitutes a particular source of stress. It can be defined as repeated, improper treatment of employees and may threaten their health and safety. In 2001, the EU member countries carried out a survey which showed that 9 % (i.e. aproximately 12 million) employees were victims of harrassment at the work place in the year 2000. Workplace violence constitutes rude behaviour as well as physical or oral violence. Environments likely to be subject to such kind of violence are primarily service activities. The results of the above survey showed that 4 % of the active population were victims of physical violence, while many more were subject to threats, insults and other forms of psychological violence.

Physical work conditions. When the physical conditions of work are unsuitable or even dangerous, they may cause various diseases as well as act as stress factors. Such conditions of work include, for example, noise, vibrations, dust, extreme temperature, dangerous substances and light. In the EU, 25 million workers are exposed to excessive noise, 8 % of them are in contact with dangerous substances, 17 % of workers inhale dust, smog or humid air half their working day, 17 % of them are exposed to various vibrations, 12 % to high temperatures and 13 % to low temperatures, 20 % of workers carry or move heavy burdens, and 32 % of them work in fatiguing positions and/or positions inducing pain (Levi, Levi, 1990).

3.2. Causes of stress outside work

Work is one of the most important activities for people living in a modern, market oriented society. It is, however, not the only one. Thus, events occuring outside work settings often generate stress within these people. Since stress usually does not cease immediately once the event is over, the individual brings it with him/her to the organization in which s/he is employed. Many factors outside work settings contribute to stress in this manner. Most, however, fit into two broad categories: stressful life events and daily hassles.

Stressful life events: Although one may live a truly "magic" life, one probably will experience traumatic events or changes, such as death of spouse, divorce, injury to one's child, unwanted pregnancy or retirement. What are the effects of such events? This question was studied first by psychologists, who asked a large group of people to assign arbitrary points (from 1 to 100) to various life events according to how much readjustment each of these events had required (Greenberg, Baron, 2000). The greater the number of points assigned to a given event, the more stressful it was considered to be for those who had experienced it. Some of the values assigned to various stressful life events are shown in Table 1.

The hassles of daily life: The traumatic life events mentioned above are highly stressful, but they are luckily rather rare. Many people live for years or even decades without experiencing even a single one. This, however, does not mean that such individuals live totally tranquil lives. In one's life, one has to cope with numerious minor irritations on a daily basis. These may be of low intensity, but of high frequency in occurrence. We can call them the daily hassles (too many things to do in a short time period), financial hassles (concern about making money) and hassles of parenthood (assistance with studying, bringing up children). These daily concerns so typical of everyday life, are an important source of stress, too. The more daily hassles people experience, the higher their level of self-reported stress. A high level of stress, of course, may have an unfavorable impact upon one's health and other aspects of life. Clearly, even minor daily concerns may be very important, so they should not be overlooked. This is especially true if they show up in synergies.

3.3. Individual differences and stress

Some people are more successful in facing stressful situations, while others respond to them with a greater level of stress. What is it that differentiates people with regard to their ability to handle stress? In searching for the answer, the explanation of these dimensions can help: 1. individual self-perception and power, 2. locus of control, 3. type A/B behaviural pattern, 4. negative orientation, and 5. ability.

Individual self-perception and power. Positive or negative self-perception affects the way in which an individual handles stressful life events. One of the more important facets of self-perception is self-esteem referring to one's good or bad opinion about oneself. People who have a positive and a reasonably accurate concept of "self" have high self-esteem. They have confidence in themselves, they know their capacities and potential and act accordingly. Self-esteem seems to moderate how one responds to stressors (Nowack, 1986). People with low self-confidence tend to have more intensive reactions to high stress than those with higher self-confidence (Davis et al., 2000).

Locus of control. Some people believe that they are masters of their own fate, while others think that what happens to them in their lives is due to luck or chance. The first type, those who believe that they control their destinies, have been labeled internals, whereas the latter, who see their lives as being controlled by outside forces, have been called externals. A person's perception of the source of his/her fate is termed the locus of control. Internals manifest stress in different ways from externals. Internals faced with a stressor are more likely to believe that they can have a significant effect on the outcomes as well as on the consequences of the stress circumstances affecting them. Hence, they tend to take control over events. Externals faced with a stressor are more likely to be passive and defensive. Rather than doing something to reduce the stress, they acquiesce to it. So externals are also more likely to experience stress than those who cope with it with more courage and confidence (Davis at al., 2000).

Type A and B behavioral patterns. Two cardiologists, Friedman and Rosenman, while conducting their research on the effects of stress upon the heart, divided people into type A and type B. According to the two researchers, type A people are three times more likely to have a stroke or a hart attack than those in type B, even if they are doing the same kind of work and/or living in similar conditions. Type A individuals are action and results oriented, and in a hurry to complete work and move on to the next task. They are highly competitive, impatient with others and get irritated when they find their situation prevents them from achieving their goals. The type B behavior pattern manifests the oposite. Those who exhibit this pattern tend to be less aggressive, less competitive, and more relaxed. They rarely demonstrate high levels of emotion even in a crisis or emergency (Hellriegel, Slocum, 2004).

Flexibility and rigidity. Flexible people experience different stressors and have different stress reactions than rigid people (Davis at al., 2000; Pettinger, 2000). It is characteristic for flexible personalities that they are relatively adaptive to change, somewhat free and open and responsive towards others. They may show some indecisiveness because they may struggle more with decisions. The flexible person does not have clear-cut rigid rules for handling situations. The rigid person is closed-minded, and generally somewhat dogmatic towards life. Rigid people have a preference for neatness and orderliness. They are also inconsiderate of others, tend to be critical in judging others, and are not very tolerant of others' weaknesses. A rigid person responds to stressors differently than a flexible person. S/he may spend more time and effort on the job in an effort to achieve more and ignore other facets of his or her life.

4. MANAGING STRESS IN WORK SETTINGS

All individuals, both those who are less sensitive to the negative effects of stress and those who are in terms of their personality more exposed to the physical, psychological and behavioural consequences of stress, can manage stress in their lives quite effectively by means of individual strategies (Plozza, 1994). Among the strategies that have proved successful in managing stress so far are, for example, regular physical exercise, meditation as well as the application of other techniques for relaxation (Kezele, Hampamer, 2002; Singh, 1996), lifestyle management and time management (Ferner, 1995; Tyrer, 1987).

In organizations, two methods of helping employees reduce stress may be applied. The first is connected with the factors causing people stress. In section 4 of this paper, these factorswere classified into the factors that occur in work settings and the factors that exist outside work settings. The organizations that endeavor to assist employees in managing stress may primarily influence the first groups of factors. The second way of helping the employees to manage stress concerns the formation of various programs that are oriented to maintaining the wellbeing of employees and the prevention of stress.

We shall primarily turn our attention to the first of the two above mentioned ways of helping employees with stress reduction. Within the organizations, employees may even develop various strategies for managing the factors that cause stress among employees in work settings.

4.1. Strategies for managing stress

The purpose of strategies for managing factors that cause employees in organizations stress is the reduction or total elimination of stress from their work. Those strategies are:

* creating a favorable organisational climate,

* job enrichment,

* reducing conflict and precise definition of roles,

* planning and developing career,

* effective leadership,

* developing communication capabilities,

* motivating employees,

* job satisfaction,

* mutual relations.

Creating a favorable organizational climate. In many organizations that have an unfavorable, infexible and impersonal climate it emanates to a large extent from the strictly formalized levels and relations between employees. Such a climate creates stress in work settings and reduces the effectiveness of employees. In those organizations, a strategy reducing the stress within employees should be accepted. This would be based on designing a more decentralized and employee-friendly structure and on participative business-decision making as well as on communication flow from lower to upper decision making levels.

Job enrichment. Work assignments in organizations are often designed without considering the motivational aspect and job satisfaction of employees.Such a state in structure and job content may cause stress among employees. Therefore, bosses should also consider job enrichment when designing a particular job. This dimension refers to a great extent to the improvement of job content as well as its characteristics. The content factors include, for example, responsibility, independence, recognition, possibility of success, promotion and growth. The basic characteristics of the job include skill variety, task identity, task significance, autonomy and feedback (Treven, 1998). Jobs designed to consider the dimension of job enrichment constitute a less stressful factor for employees in work settings than those in which job enrichment is not taken into account in the process of job designing.

Reducing conflict and precise definition of roles. We have defined role conflict in work settings and the personal role of an employee in section 4 as two of the important stress factors. To what extent those two factors cause stress within employees depends primarily on managers and their capability for a precise delimitation of their subordinates' roles. For each job, the expectations regarding its implementation and what information as well as other resources the employees need to carry out their work efficiently should be determined

Planning and developing career. Strategy of planning and developing a career was mentioned as one of the strategies for reducing stress within employees in organizations. Managers usually do not show too keen an interest in the career of their subordinates who are, hence, left alone to decide about their careers. Such a situation can be compared with the state of students at a large university who may only use a computer if they want to obtain specific advice about their courses. A possible consequence of such a state may give rise to some doubt and stress in students.

Effective leadership. Nowadays the efficiency of organizations depends to a large extent on the bosses' capability to organise and lead their employees. Modern organizations require a different style of leadership and management, i.e. one that allows for creative and innovative work (Treven, 2001). People are no longer satisfied if they are treated as machines. Employees today are better educated, so their wishes must be considered. This brings about change. Organizational culture is getting more human and humane (Evans, 1993). In organizations we need managers who are able to stimulate human resources, motivate them and apply their capacities (Braja, 1996; Udovièiè, 2004).

Developing communication capabilities. Well developed communication improves work productivity, increases a sense of affiliation and makes the employees aware that their superiors appreciate their opinions. Workers need precise and accurate information in order to perform their work well. Close cooperation between coworkers depends primarily on first class information. The worker who is not acquainted with novelties in his/her field will feel lonely and abandoned, therefore s/he is not able to evaluate the work process or his/her own work properly (Trstenjak, 1979). Feedback on the implemented work may also constitute a strong motivator.

Motivating employees. Work motivation can be defined as a force that influences the behavior of employees in the organization (George, Jones, 1996). The essence of work is the strongest motive to drive employees so we must stir up their interest in it. They must be shown that they are important to us, that we respect them, appreciate their work, and want them to learn, grow and develop their abilities. That is the best motivation we can give (Carnegie et al, 1995; Udovièiè, 2004).

Job satisfaction .Job satisfaction is not merely when the employees earn good salaries or have opportunities for promotion. It can also be influenced by internal factors like: work achievement, appreciation of work done, responsibility, good working conditions as well as external factors, such as: appropriate policy and management in the organization, adequate leadership and good mutual relations (Moina, 2002). Factors that may increase one's job satisfaction and reduce stress include: challenge, success, appreciation, rewards, appropriate level of responsibility, control over one's own work, work with pleasant people, loyalty to the organization, and clearly determined roles, aims and priorities.

Mutual relations. Mutual relations between coworkers and work groups are dimensions of our personal experiences of the organization (Maslach, Leiter, 2002). Good work relations reduce the impact of stress and diminish tension (Davidson, 1997).

4.2. Programs for managing stress with employees

Special programs may also help employees to manage their stress more effectively. The most often applied programs of this kind are:

* stress management programs,

* wellness programs,

* employee assistance programs.

Stress management programs are developed in organizations to acquaint employees with various techniques such as meditation, joga, relaxation training and lifestyle management.. Their intention is to teach the individual how to effectively reduce stress in his/her life. Many organizations in USA have applied such programs in the last few years as they have found that the effects of those programs are also positive from the cost point of view. Those organizations that cannot afford to create their own programs contact external consultants to help them choose an appropriate program for training of employees on stress management. They may also decide to purchase audiovisual programs or videocassettes.

Stress management programs may consist of various workshops in order to introduce employees to the topics of stress and stress management. Such workshops can give the employee general knowledge about the causes of stress, its consequences and stress management methods or they can be directed to the training of an employee in a particular technique.

The employees who attend the general stress management workshop benefit in many ways. First, they are aquainted with the nature of stress and how humans respond physically and psychologically to stressful situation. Second, they are informed about the specific stressors and symptoms that cause them the most difficulty in their lives and work settings. Third, they are educated about the possible consequences of stress.

Wellness programs have been developed to help employees to maintain their physical and mental health. A healthy person can manage stress more easily than the one suffering from phobias, nightmares, lack of appetite, heart disease or other health troubles. Typically, wellness programs consist of workshops that train employees how to perform some of the stress reducing individual behaviors, such as losing weight, exercising, giving up smoking and the like. Although organizations provide the relevant knowhow, the individual employees are responsible for taking control over their own lives. Organizations that provide wellness programs for their employees consider such programs a sensible investment with positive financial effects. The employees able to manage stress effectively enjoy better health which in turn means reduced abseentism from work because of illness and greater productivity.

Employee assistance programs support employees assistance in facing all kinds of problems, such as career planning, financial and legal advice and others (Newton, 1995). The application of such programs has been in use for quite some years in the USA; and in Western Europe and in Slovenia it is also increasing.

5. CONCLUSION

Stress is a universal experience in the life of every company and every executive, manager, and individual employee. It is a naturally occurring experience which may have beneficial or destructive consequences. The destructive consequences of a stressful experience are not inevitable. They only result from ineffective management of stress and stressful events. The thesis of this paper is that the destructive consequences of stress in companies may be avoided through the appropriate strategies and programs for stress prevention in work settings.

References

REFERENCES

1. Braja, P. (1996). Sedem skrivnosti uspenega managementa Ljubljana: Gospodarski vestnik.

2. Brewer, S. (1999). The ultimate stress buster. London: Ebury Press.

3. Carnegie, D., Stuart, R.L. & Crom, A. (1995). Kako uspeno vodimo ljudi Ljubljana: Mladinska knjiga.

4. Cooper C.L., Dewe, P.J. & O'Driscoll M.P. (2001). Organizational stress. London: Sage Publications.

5. Davidson, J. (1997). The Complete idiot`s guide to managing stress. New York: Alpha books.

6. Davis, M., McKay, M. & Robbins Eshelman, E. (2000). The Relaxation and stress reduction workbook. New Harbinger Pubns Inc.

7. Evans, R. & Russel, P. (1992). Ustvarjalni manager Ljubljana: Alpha Center.

8. EU (2000). Communication from the Commision to the Council and the European Parliament: Innovation in a Knowledge-driven Economy.

9. Ferner, J.D. (1995). Successful time management. New York: Wiley.

10. George, J.M. & Jones, G.R. (1996). Understanding and managing organizational behavior. Addison - Wesley Publishing Company.

11. Greenberg, J. & Baron, R.A. (2000). Behavior in organizations. Prentice Hall.

12. Helllriegel D. & Slocum, J.W. Jr. (2004). Organizational behavior. Mason, Ohio: Thomson South-Western.

13. Kezele, A.P. & Hampamer, A. (2002). 108 pitanja o integralnoj meditaciji (angl. 108 questions about integral meditation) . Èakovec: Dvostruka Duga.

14. Levi, L. & Levi, I. (1999). Guidence on work-related stress: Spice of life - or kiss of death?, http://europa.eu.int/comm/employment_social/ health_safety/publicat/stress_en.pdf, 28.8.2003.

15. Looker, T. & Gregson, O. (1993). Obvladajmo stres: kaj lahko z razumom storimo proti stresu. Ljubljana: Cankarjeva zaloba.

16. Luban Plozza, B. & Pozzi, U. (1994). V soitju s stresom. Ljubljana: DZS.

17. Markham, U. (1995). Managing stress: The stress survival guide for today. Dorset: Element.

18. Maslach, C. & Leiter, M.P. (2002). Resnica o izgorevanju na delovnem mestu. Ljubljana: Educy.

19. Mc Clean, A.A. (1980). Work stress. Reading: Addison-Wesley.

20. Moss Leonard, M.D. (1981). Management stress. Reading: Addison-Wesley.

21. Moina, S., et al. (2002). Management kadrovskih virov Ljubljana: FDV.

22. Newton, T. (1995). Managing stress. Sage Publications Inc.

23. Nowack, K. (1986). Who are the hardy?. Training and Development Journal, 40, str. 11- 118.

24. Pettinger, R. (2002). Stress management. Capstone Publishing (A Wiley Company).

25. Ross, R.R. & Altmaier, E.M. (2000). Intervention in occupational stress. London: Sage Publications.

26. Schmidt, A. (2001). Najmanj kar bi morali vedeti o stresu. Ljubljana: Kmeèki glas.

27. Selye, H. (1976). The Stress of life. New York: McGraw-Hill.

28. Selye, H. (1986). Stress in health and disease. London: Butterworths.

29. Singh, R. (1996). Meditacija. Ljubljana: Tangram.

30. Treven, S. (1998). Management èlovekih virov Ljubljana: Gospodarski vestnik.

31. Treven, S. (2001). Mednarodno organizacijsko vedenje Ljubljana: Gospodarski vestnik.

32. Trstenjak, A. (1979). Psihologija dela in organizacije. Ljubljana: Dopisna delavska univerza.

33. Tyrer, P. (1987). Kako iveti s stresom Ljubljana: Mladinska knjiga.

34. Udovièiè, K. (2004). Metode nematerialne motivacije managerjev v tranzicijskih podjetjih. PhD disseration. Maribor University, Faculty of Economics and Business, Maribor.