Partnership or corporation? Private or public? Adhocracy or professional bureaucracy? It is very easy to think of the governance of professional service firms in terms of these simple dichotomies.

But of course it is much more complicated than that. Not only are there a variety of forms of governance prevalent within the sector, but a single firm will adopt many of them over time as it grows and matures.

The following model builds on Greiner's influential model of the phases of organisational growth, and adapts it to reflect the specific governance issues of professional service firms. The process illustrated in the model is not necessary sequential, linear, or inevitable. Indeed, the transitions tend to reflect crisis points that either drive the firm forward to the next stage, or lead to a reversal in its progress.

Professor Laura Empson is the Director of the Centre for Professional Service Firms at Cass Business School.