Instructional Science 16:19-34 (1987) 19 © Martinus Nij'hoff Publishers (Kluwer), Dordrecht- Printed in the Netherlands The new Component Design Theory: instructional design for courseware authoring 1 M. DAVID MERRILL Department of Educational Psychology, University of Southern California, Los Angeles, USA Abstract This paper outlines extensions of Component Display Theory to provide the type of design guidance needed for experiential computer based instructional systems. The new Component Design Theory (CDT) extends the original theory in several significant ways. Content types are extended to content structures. These content structures include experiential as well as structural representations. Primary presentation forms are extended to primary presentation functions and the display is replaced by the transaction. Various types of transactions are identified for both structural and experiential represen- tations. Course organization, previously described as Elaboration Theory, is included as part of the new CDT. Consistency ruies are extended to include: (a) goal-content representation consistency; (b) goal/ content representation - transaction consistency; and (c) goal/content representation - course organiza- tion consistency. Intervention rules are included for intra-transaetion guidance, inter-transaction selec- tion and sequence (strategy), inter-content representation selection and sequence (sequence) and control (who makes the guidance, strategy and sequence decisions, the learner or the systean?). Finally a set of cardinal instructional principles is identified and the sets of roles which comprise the new CDT are sug- gested as prescribed procedures for implementing these cardinal principles. Introduction Over the past decade we have described and evaluated Component Display Theory, an instructional design theory (see Merrill & BoutweU, 1973; Merrill & Tennyson, 1977; Merrill, Reigeluth & Faust, 1979; Merrill, 1983; and Merrill, 1987a). The descriptive parts of thistheory consist of a performance/content matrix for classi- fying instructional outcomes and primary and secondary presentation forms for describing presentation displays. The prescriptive parts of this theory consist of consistency rules which suggest that learning, resulting from inslruction, will be most efficient and effective if certain combinations of primary and secondary pres- entation forms are used to promote a given class of performance/content outcome. Further prescriptions suggest that adequate instruction, for a given performance/ content class, requires the use of certain secondary presentation forms and types of relationships between primary and secondary presentation forms. The theory also promoted learner control as a mechanism for adapting to individual differences. Because of increased computing capability and availability, and with an in- creased interest in "intelligent" CAI, instructional capabilities now exist which were not previously practical. However instructional design theory has not kept pace with the increased capabilities in hardware and software.