Title: Distributed problem formulations for the design of complex systems Multidisciplinary optimization (MDO) is a collection of systematic approaches to the design optimization of complex, coupled engineering systems. Multidisciplinary systems, such as aerospace vehicles, involve optimization with respect to many aspects, or disciplines, of the design problem. The expense and difficulty of treating MDO problems as conventional NLP has motivated researchers to propose alternative optimal design problem formulations and attendant optimization algorithms. The proposed approaches usually involve some degree of problem distribution. We discuss the effect of the degree of distribution on the tractability of the resulting optimization problem. We propose a dynamic approach to problem formulation for MDO that takes advantage of the problem structure, maximizes disciplinary autonomy, and allows for interchangeable problem statements to be used depending on the available resources and the characteristics of the application problem.