It sheds no light on the question of where Clara Eliot pursued a doctorate, but Fisher acknowledges her help in the Preface to Theory of Interest (1930).  So there was an ongoing professional association.  Searchable full text is available at

http://www.econlib.org/library/YPDBooks/Fisher/fshToI.html 

  "In preparing this book I have received suggestions and assistance from so many economists and others in the United States and abroad, that it is impracticable to mention them all by name. My associates, Dr. Royal Meeker, Dr. Max Sasuly, and Mr. Benjamin P. Whitaker, have contributed in helpful criticism, as well as in gathering material, preparing the manuscript for the printer, and reading the proof. I am especially indebted to my brother, Mr. Herbert W. Fisher, for his suggestions as to style and the manner of presentation, and to Professor Harry G. Brown for his criticism of my statement of the opportunity principle. Others who have helped me especially are: Prof. Lionel D. Edie, Mr. C. O. Hardy, Mr. R. G. Hawtry, Prof. Frank H. Knight, Prof. J. S. Lawrence, Prof. Arthur W. Marget, Prof. H. B. Meek, Prof. Wesley C. Mitchell, Mrs. Clara Eliot Raup, Prof. Henry Schultz, Prof. Henry R. Seager, Mr. Henry Simons, Mr. Carl Snyder, Prof. Jacob Viner."


Scott Cullen