A research plan is a thoughtful, compelling, well-written document that outlines teachers exciting, unique research ideas that they and their students will pursue over the next half decade or so to advance knowledge in their discipline. It must be a document that people at the department you hope to join will (a) read, and (b) be suitably excited about to invite you for an interview.
The research plan is the main part of a grant application describing a principal investigator's proposed research, stating its importance and how it will be conducted. A typical research plan has four main sections:
A. Specific Aims
B. Background and Significance
C. Preliminary Studies and Progress Report
D. Research Design and Methods
The research plan should be written to address the following questions:
What do you intend to do?
Why is the work important?
What has already been done?
How are you going to do the work?