The law of comparative advantage
a busy station, by Terry Freedman
As head of computing, you are most likely better at programming and better at using spreadsheets than other teachers in the school. However, if you are RELATIVELY ie COMPARATIVELY better at programming than spreadsheets, it might well be more efficient and efficatious for you to focus on creating resources for teaching programming, and to delegate to a team member the creation of resources for teaching spreadsheets. In other words, the law of comparative advantage is a more sophisticated version of the division of labour.