Introduction
Effective leadership is important to the success of any organizations. With effective leading, managers send a clear organizational vision to subordinates and influence them to achieve certain organizational goals. As a hot topic which has been researched for decades, a lot of leadership models or theories have been created. These models demonstrated the nature of effective leadership and tried to figure out the factors which influence effective leadership. Among these models or theories are trait model, behavior model, contingency model and full range leadership model. These models help people understand the way leadership works and give suggestions about how to be better leaders in organizations. Most of the models came from experiment and lacked of application. Whether they are useful in reality is more important than models themselves. Without application, models are meaningless. However, examples of challenging occur everywhere. It is necessary to evaluate these models from the scores they get in application.

This essay will firstly discuss what effective leadership is and how effective leadership affects subordinates’ performance. Following this, it will demonstrate a clear explanation for a range of leadership models. These models include trait model which focuses on what leaders are like, and behavior model which focuses on what leaders do, and contingency model which takes consideration of the situation variables, and full range leadership model which based on the theory of transactional leadership and transformational leadership. Following each model, this essay identifies some existing problems and shortcomings in the practice of these models. Finally, it will come up with some common factors such as gender and knowledge which may affect the results in reality. It is necessary to reconsider these factors before using certain models.

Effective Leadership
Leadership is a management process. During this process, leaders can influence subordinates and enlist the aid and support of others (Chemers, 1997). During this process, leaders can inspire, motivate and direct other members’ activities and achieve group or organizational goals.Leadership is an important process in all organizations. These organizations include for-profit organizations such as companies and nonprofit organizations such as government and schools. It is also important for all lever of management: first-line management, middle-management, and top management.

In general, a good leadership needs to satisfy the needs of the organizations as well as subordinates. The needs of organizations may include healthy operations and certain profit demands. As a leader, it is his or her responsibility to maintain a good condition of the organizations. However, having a high profit does not mean leaders are effective. Effective leadership means leaders can use their power or personality to motivate subordinates and help them understand their roles in organizations. With a clear understanding of their roles and extra motivations, subordinates tend to perform at a higher level than usual. Different people hold different opinions about the question that what type of leadership is the best. Early researchers found some common traits or behaviors that effective leaders share. For example, effective leaders are people who often communicate with their subordinates. Ken Chenault, as the president of American Express Company, is respected by colleagues for his personality and open door policy. He is willing to open his door to his subordinates and listen to their voice. Some leaders can take advantage of their power and others may prefer empowerment.

Trait Model
The trait model holds the belief that certain characteristics or traits lead to effective leadership.According to this model, effective leaders have some common personal characteristics or qualities. With these characteristics and qualities, they are different with ineffective leaders and with people who never become leaders. These certain traits include knowledge, intelligence, expertise, self-confidence, dominance, high energy, stress tolerance ability, honesty and maturity (Bass, 1990). Take high energy as an example, most of the older may sleep over ten hours everyday, while Sam Walton, founder of Wal-Mart, still maintain the habit to attend Saturday morning meeting even when he is 70 years old(Shelley & Edwin, 1991).

However, there is a fact that some effective leaders do not possess all of these traits. What’s more, some leaders who do possess these traits are not effective in their leadership roles. According to Peter’s (1996) research, leaders and followers often held same kinds of characteristics. There were no differences between them with respect to traits. Sometimes, people who possessed these traits tend to be ineffective. As a result, even though this model seems to be acceptable, it does not work well in managerial field.

Generally, there are three problems. The first one is that researchers often assumed these characteristics work well in all kinds of situations. However, people may act differently from the usual ways with respect to different circumstances. For example, leaders who work on a battlefield may possess different kinds of traits with people who work in the staff room of a school (Sadler, 1997). The second problem is that these traits are not exhaustive. There is a big chance that some people possess other traits or qualities which also help them to be effective leaders. Actually, different researchers hold different opinions about this list. John (1989) observed many organizations and leaders in North American and came up with a different trait list. According to his list, these traits included physical vitality and stamina, understanding of followers and their needs, need for achievements and so on. This list was different from the list conducted by Bass. Actually, there are still many versions about trait model. As a matter of fact, it is difficult to choose the appropriate trait model in the practice of management. The third problem is that these traits concern males more than females. Most of the traits in this model described men. It is difficult to associate them with women. However, there exists a possibility that some other traits lead to the success of women. Conducting a trait list just for women is tricky in the practice of management. Actually, whether the traits of leaders can be gendered is questionable as well (Rosener, 1997).

Behavior Model
Traits alone can not determine effective leadership. As a result, researchers started to search for new explanations. They hold the opinion that what leaders actually do is more important comparing with what leaders are like. In other words, they began to look at the behaviors of effective leaders which can influence their subordinates to achieve organizational goals. Researchers at The Ohio State University indentified consideration and initiating structure as two basic kinds of leadership behaviors.

Consideration behaviorsindicate that a manager trusts, respects, and cares about subordinates.A high score in consideration is evidence of a climate of good rapport and communication (Abraham, 1996). High score owners are manager who truly care about the true needs of their subordinates and want to find ways to help subordinates. Caring about employees is a win-win strategy. On one hand, employees feel satisfied with their organizations and tend to be loyal subordinates. On the other hand, turnover rates decrease as employees care about the future of their companies as well. Nowadays, many companies realize that consideration is so important. Some of them even treat “take care of our employees” as one of their principles. However, consideration means more than a superficial “pat on the back” or “first name calling”. As a manager, one should figure out the true needs of employees (Aaron, William & Michael, 1969).

Initiating structureis behaviors that managers try to make sure certain work gets finished, employees do their job at an acceptable level and the whole organization works efficient.A high score owners in initiating structure are people who play a more active role in organizations (Abraham, 1996). Some examples of initiating structure are letting groups members know the expected results when assigning tasks, deciding the way to get job done, maintaining certain standards of performance and motivating subordinates to do a better job (Judge, Piccolo & Ilies, 2004). For example, managers in a big store need to discuss the latest designs with their subordinates so that they are knowledgeable with customers. Managers also need to encourage their employees to provide high-quality customer service and to avoid a hard-sell approach. By influencing employees, managers can exert influence on customers indirectly.

According to this model, consideration and initiating structure are independent behaviors. Leaders who perform consideration do not affect their performance of initiating structure. Leaders tend to be effective when their stores are high both in consideration and initiating structure.

However, some leaders are effective even though they do not perform consideration or initiating structure behaviors. What’s more, some leaders are ineffective even when they do perform both kinds of behaviors. Actually, the relationship between leader effectiveness and performance of those two behaviors is not clear-cut. The main reason is that this model fails to take situational variables into account (Steven, Chester, Charlers & Ralph, 1974). In reality, there are many different situations.  Behaviors which make a manager an effective and efficient leader in one situation are different from those in another situation. For example, an effective leader in a clothing store might not be an effective coach of a football team. Even in the same industry, a first-line manager who gets good performance in leadership may have no ability to be an effective middle level manager. As a result, this model is hard to practice in reality. There is a big chance that companies may miss the potential effective leaders just because they do not perform certain behaviors.