手法を比較

	Board Interlock Network Analysis	Merger and Acquisition Performance Event Study
分野	経営戦略論	経営戦略論
系統	Process / pipeline	Process / pipeline
提唱年	1996	2001
提唱者	Mark S. Mizruchi; Gerald F. Davis	Gregor Andrade, Mark Mitchell & Erik Stafford; David King, Dan Dalton, Catherine Daily & Jeffrey Covin
種類	Network-analytic pipeline for inter-firm ties created by shared directors	Event-study pipeline for the wealth effects of merger and acquisition announcements
原典	Mizruchi, M. S. (1996). What do interlocks do? An analysis, critique, and assessment of research on interlocking directorates. Annual Review of Sociology, 22, 271-298.	Andrade, G., Mitchell, M., & Stafford, E. (2001). New evidence and perspectives on mergers. Journal of Economic Perspectives, 15(2), 103-120.
別名	Interlocking Directorate Analysis, Director Interlock Network Analysis, Corporate Board Network Analysis, Intercorporate Network Analysis	M&A Abnormal Returns Analysis, Acquisition Announcement Event Study, Acquirer-Target Wealth Effects Analysis, Deal Announcement CAR Analysis
関連	3	3
概要	Board interlock network analysis treats the corporate economy as a network in which two firms are tied whenever they share a director, and studies how these interlocking directorates channel information, influence, and the diffusion of practices among companies. Mizruchi's 1996 Annual Review of Sociology synthesis crystallized the field, distinguishing the determinants of interlocks from their consequences and cataloguing the mechanisms — collusion, cooptation and monitoring, legitimacy, career advancement, and social cohesion — that interlocks have been argued to serve. Davis's 1991 study of how the poison-pill takeover defense spread through the board network gave the perspective its canonical demonstration that corporate practices diffuse along director ties. The method combines two-mode-to-one-mode network construction with positional metrics and diffusion modeling.	A merger and acquisition event study measures the stock-market reaction to a deal announcement to infer how much value the deal is expected to create or destroy for acquirers and targets. The logic is that in an efficient market the share-price jump around the announcement capitalizes investors' revised expectations of future cash flows attributable to the deal. Andrade, Mitchell and Stafford's 2001 survey distilled the empirical regularities: targets earn large positive abnormal returns, combined acquirer-plus-target returns are modestly positive, while acquirers themselves often earn around zero or slightly negative returns. King, Dalton, Daily and Covin's 2004 meta-analysis confirmed that acquirers, on average, do not gain and pointed to unidentified moderators, motivating cross-sectional models that link abnormal returns to deal and firm characteristics.