Conventional project-management tools--PERT charts and Gantt charts, for example--were created to help manage sequences of discrete tasks that make up large construction projects. Yet these tools don't capture clearly the back-and-forth of information that takes place in innovative processes, such as product development. Conventional tools are designed to answer the question, "What other tasks must be completed before I begin this one?" But product development planners, especially in high-tech businesses, need tools that answer a very different question: "What information do I need from other tasks before I can complete this one?" The author describes the Design Structure Matrix (DSM), a project management tool that focuses on representing the information flows of a project rather than its work flows. He explains how the DSM works and how to use it to make development processes more efficient. A project DSM can show which information exchanges involve design iteration and how well a process anticipates the need for rework. In addition, the author suggests four ways to improve a company's information flows: rearranging the sequence of tasks, reconsidering the organization of tasks, reducing the number of information exchanges, and managing unplannable work. By stripping away the mystery around information exchange during innovation, the DSM can give managers far more control over their most risky and expensive projects.