There is considerable need for further inquiry on this topic of board structure and shareholder returns. In particular, longitudinal inquiry is needed into cause and effect. There is also need to follow the lead of Rechner and Dalton (1989) and utilise more sophisticated, market-based measure which adjust for risk. Moreover, the effect of CEO duality on shareholder returns and corporate performance generally may be contingent upon some institutional factors such as size or complexity (Fama and Jensen 1983) as yet empirically unidentified. These are issues for future research.