This study has some limitations that are useful for further research. Next to these three levels of leadership, there is another approach with three levels, which can also be a research approach. These are “attempted leadership”, when person A accepts the goal of changing person B and can be observed attempting to do so, “successful leadership”, when person B changes his or her behaviour as a function of person A’s effort and “effective leadership” as a consequence of a changed behaviour of person B due to efforts of person A, person B will be more satisfied, better rewarded and attain a goal of mutual importance of person A and B. Rensis Likert also specified between four leadership styles. Exploitive authoritative, is when the leader has low concern for people and uses such methods as threats and other fear-based methods to achieve conformance. Communication is almost entirely downwards and the psychologically distant concerns of people are ignored. Benevolent authoritative is similar to transactional leadership. The leader uses rewards to encourage appropriate performance and listens to the employees of the organization. Consultative leadership describes a leader that tries to listen carefully to all ideas, but is hindered due to the hierarchical style of the organization. Participative leadership is when the leader engages with people lower down the organization in decision-making. This is supported by a close organizational culture, where people are psychologically connected.Vrije Universiteit Amsterdam 29.01.2018Academic Skills However, for the purpose of my study, i choose the ones of Bass from 1985, otherwise there would be too many variables to it. To avoid error variance, a research study should be reliable and valid. Validity means that a test has measures which are useful and give the correct data. I tried to achieve that by choosing random persons and asking the same questions to every participants. Reliability goes even further and names the character of data that is consist and stable, so the gathered result of the data does not change if you do another research attempt.A common method bia might happen, because i only ask one person to both variables, in this sense, they might be influenced for my data set. But otherwise I would need to ask each time another subordinate from the same leader about their type of leadership, my first set of questions and the satisfaction of their job to another subordinate of the same leader. This would make it much more difficult to gain a sufficient set of data. Concerning research ethics, my technique with questionnaires is not interfering with human or an animals moral principles. The only thing one could claim is that the participants might not be willing to share the information as it is not in their interest or goes against their and their leaders private sphere. But in that case, these do not need to answer.