Oddly enough, not much has been done to address project leadership from a situational perspective. However, Dennis Slevin and Jeffrey Pinto have provided some useful insight. Using research based on responses to two questions, they describe the results in the context of a grid consisting of a Y-axis reflecting input to decision and an X-axis for decision authority. The two questions asked: When do you get information input (decision input)? and Where should you place the decision authority for this problem (decision authority)?
The authors identify four leadership skills: Autocrat, Consultative Autocrat, Consensus Manager, and Shareholder Manager. The Autocrat, of course, obtains little or no information from subordinates and makes decisions unilaterally. The Consultative Autocrat obtains input from subordinates , but makes most of the decisions him- or herself. The Consensus Manager receives group input and allows the group to make decisions. The Shareholder Manager does not encourage and does not take responsibility for obtaining input and allows the group to assume ultimate authority for decision making.
Slevin and Pinto appear to prefer styles leaning towards a people orientation. However, they explicitly subscribe to the situational or contingency approach to leadership, observing that no style fits all situations. They also add that the successful manager should be flexible by matching one's leadership style to the circumstances facing them. 
R. Max Wideman of AEW Services and Aaron J. Shenhar of the Stevens Institute have observed that a relationship exists between project management style and project type. Based on the work of Dr. Shenhar, they observe that style makes a difference as the technological complexity increases . Both authors identify a typology created by project management scope and technological uncertainty. They also identify four types of project leaders : Explorer, Coordinator, Driver, and Administrator.
The Explorer is the visionary who thinks strategically. The Coordinator is the facilitator who seeks compromise and encourages team participation. The Driver has a penchant towards actions and tends to be pragmatic and focused. The Administrator seeks stability and is very analytical.
Of course, Wideman and Shenhar do not appear to embrace a particular style. Again, flexibility in adapting styles to the situation is important. Both agree once again that no particular leadership style can accommodate all circumstances. Flexibility, therefore, becomes key to success. If project managers are inflexible , the affect on a team can be demoralizing. They also note that a high correlation exists between the type of leader and product, as well as the phase of a project.  A mismatch among all three can have negative results. 
Ralph Kliem and Harris Anderson apply the principles of Organizational Engineering (OE) to determine the most appropriate style under certain situations. OE is a branch of knowledge that seeks to understand, measure, predict, and guide the behavior of groups. The basis of OE is a person's strategic style, which is the behavior pattern that a person consistently manifests over a period of time when responding to situations. A strategic style is determined through two dimensions: method and mode. Method is the preferred approach to decision making, structured or unpatterned; mode is the preferred response, thought or action. The combination of method and mode creates four strategic styles: Reactive Stimulator, Relational Innovator, Logical Processor, and Hypothetical Analyzer.
A Reactive Stimulator is someone who is fast, direct, energetic , and independent when dealing with situations. A Relational Innovator is someone who is flexible, spontaneous , relational, theoretical, innovative, and futuristic. A Hypothetical Analyzer is someone who is analytical, definitive, conceptual, divergent , and reserved. A Logical Processor is someone who is practical, logical, methodical, precise, steady, and predictable.
According to Kliem and Anderson, a person's strategic style has implications for how they approach leading a project. A Reactive Stimulator prefers doing, has a task-orientation style, uses informal power, and applies negative incentives. A Relational Innovator prefers managing, has a people-orientation style, uses informal power, and applies positive incentives. A Hypothetical Analyzer prefers managing, has a people-orientation style, uses formal power, and applies positive incentives. A Logical Processor prefers doing, has task-orientation style, uses formal power, and applies negative incentives. 
The authors stress the importance of matching a person's strategic style with the overall style of a team. Otherwise, he or she will find it difficult to communicate and coordinate with team members . This situation can create such tension that it slows progress or even stops it. 
 Dennis Slevin and Jeffrey K. Pinto, Project leadership: understanding and consciously choosing your style, in Leadership Skills for Project Managers , Jeffrey K. Pinto and Jeffrey W. Trailer, Eds., Project Management Institute, Newtown Square, PA, 1998, pp. 29 “43.
 Max R. Wideman and Aaron J. Shenhar, Optimizing Project Success by Matching PM Style with Project Type, http://www.pmforum.org/library/papers/PM_Style&Scss.pdf, p. 12.
 Max R. Wideman and Aaron J. Shenhar, Optimizing Project Success by Matching PM Style with Project Type, http://www.pmforum.org/library/papers/PM_Style&Scss.pdf, p. 13.
 Ralph L. Kliem and Harris B. Anderson, The Organizational Engineering Approach to Project Management , St. Lucie Press, Boca Raton, FL, 2003, pp. 119 “130.
 Ralph L. Kliem and Harris B. Anderson, The Organizational Engineering Approach to Project Management , St. Lucie Press, Boca Raton, FL, 2003, p. 136.