What is a Dissertation Committee? 
Topic 1: Types of Ed. D. Dissertations

Every dissertation is guided by a faculty chair and a committee. The size and composition of the committee can vary by the degree program and one’s stage in the process. The role of the chair is discussed more in Unit 2, but the role of the committee covers four areas:

1.  a check and balance on behalf of the University (degrees shouldn’t be determined by one person; multiple expert eyes can ensure consistent quality); 
2. multiple sources of expertise (as no one faculty member knows it all, even if we act like it, it’s helpful to have a diverse range of expertise on the committee to assist you); 
3. multiple sources of support (similar to expertise, each committee member brings a different degree of accessibility and style of support); and 
4. accountability (to ensure that the dissertation is judged on its merit) (Garger, J. (2011). 
   

http://johngarger.com/articles/dissertations/the-role-of-the-dissertation-committee