Designers are interacting with an increasing number of digital tools in their design process; however, these are usually in addition to the traditional and ubiquitous paper-based design journals. This paper explores the medium of informal design information and its relationships with sketching behavior over three stages of the design process: preliminary investigation and user needs analyses, concept generation and development, and prototyping and testing. Our test bed consists of tangible, digital, and hybrid design journals collected from four semesters of UC Berkeley's graduate level, multidisciplinary course titled "Managing the New Product Development Process: Design Theory and Methods." We developed protocols for two categories of analysis: one that codes for the media type of each journal and its content, and another one that characterizes the content within the journal. We found a trend toward hybrid digital-tangible journals for the engineering students over the 4-year period. These hybrid journals exhibited a higher degree of detail over advancing design stages, which has been shown to correlate with improved project performance. We also present several case studies of unusual design journals that illustrate the range of designers' interpretations of design journals as a medium. Based on this descriptive research, features for interactive hybrid tangible-digital design journals are recommended.