A major problem for curriculum and course planners is coping simultaneously with the expanding knowledge base and having less time to teach. A widely used solution is to include huge amounts of information in the curriculum. A better solution is to identify a manageable core of relevant knowledge. One way is to begin with program goals and systematically identify content with increasing specificity that would be needed to achieve those goals. Another is the empirical determination of content, which has not been widely attempted. These studies would include experiments and practice analyses. There is a need to mount greater and more rigorous efforts to help advance the scholarship and to provide useful information to curriculum planners. Large-scale, multi-site studies that compare the results from various methods and from different sources will be more useful to medical education generally. In these days of exploding information and technology and greater understanding of how people learn, more than ever, efforts need to be focused on finding the very specific content that will result in the best learning for our students.