ABSTRACT
In a recent review of the literature concerning business leadership and decision-making, Naomi Lamoureaux referred to the temptation for historians to offer rational narratives, to be preoccupied with the optimal, and to disregard historical contingency and alternative historical possibilities. She expressed the view that an antidote to this was a comparative approach. 1 The research reported below predates her address but is entirely consistent with that view. 2 The starting point was a discovery that there is a surprising amount of agreement among economists on the subject of product diversification and its continuing theoretical under-development. Agnosticism provides the common denominator in a literature which reveals that the meanings of diversification are diverse; that how best to define a market or industry conceptually has attracted little attention; that adequate empirical measures of product differentiation have yet to be found; that the present state of theory suggests that with product diversification ‘anything can happen’, 3 and that, at best, limited progress is being made to indicate only what may happen in markets and firms. 4
