Development editing would be best described as editing done aiming for improvement of structure and content of manuscript. It would be pertinent to mention here that development editing has been deemed relatively different from copyediting and proofreading. These would be types of editing ensuring that grammar, spelling and punctuation of the manuscript would be as per the codified rules in various kinds of reference books.
It would not be wrong to suggest that development editing would entail topics such as plot, pacing, setting and characterization. There have been no set rules to go by them. Rather, the developmental editors would be required to draw upon their experience, instincts and lifetime of heavy reading in order to assist a manuscript to reach its highest potential. A majority of published books would go through one round of developmental editing. It would be pertinent to mention here that developmental editing would not be for the weak hearted. It could lead to huge changes in the book. Chances are higher that characters would be merged; the plot could be changed along with the settings and more. However, it would be worth the effort in the end. Books that failed to undergo developmental editing would mostly be unwieldy, baggy and unfocussed.
Who would perform development editing process?
Developmental editors could be located in publishing houses where they would mostly be called as editors. Yet other names for developmental editors would be associated editors, editors-in-chief or assistant editors. Several agents have also been known to perform developmental editing jobs. However, it would vary largely in degrees. Most of the larger agencies would be having in-house editors who would edit manuscripts of the clients. It would be done either before submission or when the novel has been under the contract with publishing house.
It would come in two forms, such as substantive editing and editorial letters.