The implication for archival corporate governance research is that it is very difficult to make causal inference from cross-sectional studies of these endogenously chosen governance characteristics and any outcome variable (e.g.Demsetz and Lehn 1985). An alternative perspective is that firms are dynamically learning and moving toward their optimal governance structure(i.e., most firms deviate from the optimal choice at a point in time) As discussed in Ittner et al. (2003), this implies that observed cross-sectional differences in governance structure provide a method for assessing the accounting and economic con sequences of these factors. In order to implement this approach.we assume that firm size(measured as the natural logarithm of the market value of equity) and industrial classifi- cation(measured using two-digit SIC codes) are the two primary"exogenous" determinants of corporate governance. Thus, the residuals produced from a regression of each governance index on firm size and industry should be a measure of how far a firm deviates from the optimal" governance structure. The key assumption for this approach to be valid is that the systematic part of the regression is the appropriate governance choice for the firm. If we find similar results after adjusting for the systematic part of governance choices, then this will suggest that the results in Tables 5 to 8 are not completely confounded by econ ometric problems induced by endogenous regressor variables.