Despite the fact that technology is embodied in human as well as physical capital and that interactions among technically trained people are critical to innovation and technology diffusion, data on scientists, engineers and other professionals have not been adequately exploited to illuminate the productivity of and changing patterns in innovation. STEP convened a workshop to examine how data on qualifications and career paths, mobility, cross sector relationships, and the structure of work in firms could shed light on issues of research productivity, interactions among private and public sector institutions, and other aspects of innovation.