Abstract Careers take place within the structures of jobs and career paths which organisations evolve over time. Career opportunities for individuals are largely determined by the factors which influence the dynamics of these structures. Simple techniques exist for picturing career structures and interpreting recent career patterns. Numerical models are well established which estimate future career opportunities. Although career patterns are changing, the effective use of internal labour markets is of increasing importance. Those involved in managing careers or counselling individuals should be better informed in this area and use information to tailor career moves and development activity to the reality of where and when career opportunities are likely to be available.