[en] This report fulfills the objective of the Advanced Control Room Concepts Project to identify the major changes and establishes the appropriate categories in nuclear power plant control room designs so that a continuum of changes can be identified. A modified Delphi Technique was used for conferring with control room experts to identify the possible control room changes or concepts, and to identify the category into which these concepts belong. The results of the first Delphi conference round were then structured into a multilevel hierarchy. The top level, or focus, of this hierarchy is the control room man-machine system. The second level is the identified categories; the third level consists of modifiers to the second level; and the bottom, or fourth, level is the concepts or changes. The second round of the Delphi conference asked the panel to pairwise compare groups of related concepts as to the likelihood of their being used in a backfit or future generation control room. The results of the second Delphi conference round ranks the possible changes from the most likely to the least likely for both the related group of changes and for the top level, the control room man-machine system