Shareholder returns were measured by return on equity, that is, profit generated on shareholder funds. Such profits form the basis of return to shareholders through dividends and appreciation of stock price. The higher the ROE, the higher the gain obtainable to shareholder per dollar invested in equity in the company. The average ROE over the three years 1985 to 1987 indexed the level of ROE and registers the longer-term effect of CEO duality on the level of shareholder return. Any change in level of ROE caused by a change in board structure which persists over time should be captured by the measure. But shorter-run effects of board structure on ROE, especially of corporations which changed board structure after 1984, will not be tapped. Hence, the present measure is a conservative estimation of the impact of board structure on ROE.