"ABSTRACT: Developers have been programming for the last 30 years in a wide variety of programming languages. Over the years, we have all developed a feeling for what it is in a programming language that makes us productive as programmers. As part of the DARPA HPCS (High Productivity Computing Systems) program, we are developing models and tools to measure programmer productivity. We will describe our data gathering process, and our effort to model programmer workflows using timed markov models. timed markov models."