“One of the major elements of the dissertation that many students do not remain conscious of (or perhaps never fully think about) is that a dissertation is a highly negotiated document. From the very beginning of the project, its shape is determined by multiple players — you, the student, your chair, and your fellow committee members. Remember your proposal stage? Most likely, your initial idea for the project wasn’t the one that was approved, but instead, a revised version that you all collectively decided was the path to pursue. All along the way, you are writing and have this work reviewed by your chair, and potentially other committee members, and of course, you have the final revisions that come either right before or immediately following the defense, this time certainly coming from every member of your committee.”
Megan Kittle Autry, Director of Thesis and Dissertation Support Services in the Graduate School at N.C. State University, has more advice here.