Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for managing skills of a workforce. The methods, systems, and apparatus include actions of obtaining data from internal sources that describes internal roles and skills corresponding to each of the internal roles, obtaining data from external sources that describes external roles and skills corresponding to each of the external roles, and generating a skill relationship model that represents relationships between the internal roles, external roles, and the skills. Further includes action include, for each of the skills, determining whether a difference between a degree of relationship between the skill and an external role and between the skill and an internal role matching the external role satisfies a relationship threshold, determining whether internal future supply for the skill satisfies internal future demand for the skill, and determining whether to train current employees in the skill.