Socio-technical theory of leadership focus on the presence of two subsystems in every organization, the interrelatedness of social and technical aspects of an organization. Theory pertains to the social aspects of people and technical aspects of an organization, which means structure and processes within the organization.
Strategic Contingencies Theory is a theory of intra-organizational power. The power of a subunit or individual depends on a few contingencies and that the more contingencies are controlled by a subunit, the greater is its power. The theory focuses on tasks that need to be done in the form of problems to be solved, thus de-emphasizing personality.
The Vroom-Yetton model is designed to optimize for the current situation the leadership style for best decision-making. Its a decision model formulated with contribution from Arthur Jago on how to make group decisions. The leader must gather information from the team prior to making the decision and involves more people in the decision process.