Why do people change jobs? We have already reviewed in general terms how transitions are the product of various sources of turbulence and forces for change: people's unfulfilled needs, occupational opportunity structures, and organizational processes. But if we look to the literature of the applied behavioural sciences no coherent or integrated view of job change is to be found, which is perhaps surprising given how ubiquitous, radical and significant an event it seems to be. This is not because job change has been of no interest to social scientists, but because it has been viewed from the highly separated vantage points of different sub-disciplinary fields. Each has commented on distinctive aspects of mobility, but with quite different assumptions and methods. The result has been diverse and generally non-complementary insights.

Writers on careers constitute one group for whom mobility is a central concern, but their interest in transitions has almost exclusively focussed on early career choice processes, and beyond that they have looked for broad patterns in the development of careers (cf. Brown and Brooks, 1984; Watts et al., 1981). Their analyses, deriving from the traditions of counselling and differential psychology (the study of measurable individual differences), have focussed on how relatively stable individual factors such as personality, interest, social class, and gender, influence the career course.