Simulation of Concentration Development from Modified Gibrat Growth-Entry- Exit Processes
通过模拟修正的吉布拉过程，研究企业增长、进入和退出对市场集中度发展的影响，发现系统性企业增长最重要，而进入退出和随机增长变异影响较小。
Gibrat's law is augmented to produce a more general stochastic model of concentration consisting of growth, entry, and exit processes. Empirical facts on growth, entry, and exit reported elsewhere are employed to calibrate the model, which is then repeatedly simulated, generating concentration data for 280 hypothetical industries grouped under fourteen types. The simulated data are used to investigate the importance of growth, entry, and exit in shaping concentration development. Most important is systematic firm-level growth. Entry and exit are much less significant, as is random growth variability, which features prominently in previous stochastic models. Parallels with previous interindustry research are drawn. Copyright 1995 by Blackwell Publishing Ltd.