This paper models the interaction of firm insiders and outsiders on a corporate board and addresses the question of the board's ideal size and composition. In the model, the board is responsible for monitoring projects and making CEO succession decisions. Inside directors are better informed regarding the quality of firm investment projects, but outsiders can use CEO succession to motivate insiders to reveal their superior information and help the board implement higher value projects. The optimal board structure is determined by the trade-off between maximizing the incentive for insiders to reveal their private information, minimizing coordination costs among outsiders and maximizing the ability of outsiders to reject inferior projects. I show that optimal board size and composition are functions of the directors' and the firm's characteristics. I also develop testable implications for crosssectional variations in the optimal board structure across firms.

We identify and compare firms that promote a single executive (successor-incentive) and companies that conduct tournaments (tournament-incentive) among inside managers to succeed the CEO. Successor-incentive firms give more pay-for-performance compensation to the designated successor, are more likely in firms or industries where firm-specific human capital is more important to the CEO position and where the supply of potential outside CEO replacements is limited. In addition, these firms are associated with lower CEO turnover sensitivity to firm performance. Restricting firms that are suited for a successor-incentive promotion to a tournament-incentive promotion is associated with lower firm valuation.

Using a unique panel dataset that tracks corporate board development from a firm's IPO through 10 years later, we find that: (i) board size and independence increase as firms grow and diversify over time; (ii) board size—but not board independence—reflects a tradeoff between the firm-specific benefits and costs of monitoring; and (iii) board independence is negatively related to the manager's influence and positively related to constraints on that influence. These results indicate that economic considerations—in particular, the specific nature of the firm's competitive environment and managerial team—help explain cross-sectional variation in corporate board size and composition. Nonetheless, much of the variation in board structures remains unexplained, suggesting that idiosyncratic factors affect many individual boards’ characteristics.