This study presents evidence on the impact of outside directors on firms’ investment behavior and performance with a focus on the recent quasi-natural experiment that rapidly increased the number of outside directors in listed firms. Using a panel of Japanese firms, we compare listed and unlisted firms and conduct instrumental variable estimations to examine causal relationships. The results indicate that the rapid increase in the number of outside directors among listed firms did not promote active investments or risk-taking behavior. In addition, it had no significant impacts on the profitability and productivity of the firms.

中文翻译：

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外部董事对公司投资和业绩的影响：来自日本的一项自然试验的证据

这项研究提供了关于外部董事对公司投资行为和绩效影响的证据，重点是最近的一次自然实验，该实验迅速增加了上市公司中外部董事的人数。我们使用一个由日本公司组成的小组来比较上市公司和非上市公司，并进行工具变量估计以检验因果关系。结果表明，上市公司中外部董事人数的迅速增加并未促进积极的投资或冒险行为。此外，它对公司的盈利能力和生产率没有重大影响。