Thanks to a link on another nursing site I came across a new word:
Prosopography is an investigation of the common characteristics of a historical group, whose individual biographies may be largely untraceable, by means of a collective study of their lives, in multiple career-line analysis. Prosopographical research has the aim of learning about patterns of relationships and activities through the study of collective biography, and proceeds by collecting and analysing statistically relevant quantities of biographical data about a well-defined group of individuals. This makes it a valuable technique for studying many pre-modern societies. Prosopography is an increasingly important approach within.
I'm not sure I understand it, but have a sneaking feeling that it's what I'm doing!