We exploit a large legal shock to the board structure of Korean firms, using a strong research design—combined difference-in-differences and regression discontinuity—to study whether this board structure change affects firm financial reporting (disclosure, MD&A length, and abnormal accruals), investment and growth (sales growth and capital expenditures), and firm value (proxied by Tobin's q). We also compare results from the annual DiD/RD design to those from simpler panel and “causal” methods, and assess how results vary across methods. We find robust evidence across methods that the shock predicts improved scores on a Disclosure Subindex, confirm prior findings of an increase in Tobin's q, and find some evidence for a drop in sales growth, but no convincing evidence of significant change for other outcomes. By comparing results across methods, we illustrate how using multiple causal designs can provide insight into and evidence of robustness not available from a single design, as well as case study evidence that panel methods, simple DiD, and its close cousin, shock-based IV, can produce apparent false positives.

中文翻译：

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董事会结构对公司信息披露和行为的影响：韩国案例研究与研究设计比较

我们利用对韩国公司董事会结构的巨大法律冲击，使用强大的研究设计——结合差异中的差异和回归不连续性——来研究这种董事会结构变化是否影响公司财务报告（披露、MD&A 长度和异常应计） )、投资和增长（销售增长和资本支出）和公司价值（由托宾q 代表）。我们还将年度 DiD/RD 设计的结果与更简单的面板和“因果”方法的结果进行比较，并评估结果如何因方法而异。我们在各种方法中找到了强有力的证据，表明冲击预测披露子指数的得分提高，证实了先前关于托宾q增加的发现，并找到销售增长下降的一些证据，但没有令人信服的证据表明其他结果发生了重大变化。通过比较不同方法的结果，我们说明了使用多重因果设计如何提供单一设计无法提供的稳健性的洞察力和证据，以及面板方法、简单的 DiD 及其近亲、基于冲击的 IV 的案例研究证据，可能会产生明显的误报。