A Survey of Theories and Empirical Evidence
Chapter 4: Gibrat’s Law
Gibrat’s law continues to receive a huge amount of attention in the empirical industrial organization literature, more than 75 years after the seminal publication of Gibrat (1931). We begin by presenting the ‘Law’, and then review some of the related empirical literature. We do not attempt to provide an exhaustive survey of the literature on Gibrat’s law, because the number of relevant studies is indeed very large. (For other reviews of empirical tests of Gibrat’s law, the reader is referred to the survey by Lotti et al., 2003); for a survey of how Gibrat’s law holds for the services sector see Audretsch et al., 2004.) Instead, we try to provide an overview of the essential results. We investigate how expected growth rates and growth rate variance are influenced by firm size, and also investigate the possible existence of patterns of serial correlation in firm growth. 4.1 GIBRAT’S MODEL Let us briefly return to Gibrat’s model of firm growth presented earlier in section 2.2. As before, we define xt to be the size of a firm at time t, and let et be random variable representing an idiosyncratic, multiplicative growth shock over the period t – 1 to t. We have xt – xt−1 5 etxt−1 which can be developed to obtain xt 5 (1 1 et)xt−1 5 x0(1 1 e1)(1 1 e2). . .(1 1 et) (4.2) (4.1) It is then possible to take logarithms in order to approximate log(1 1 et) by et to obtain1...
You are not authenticated to view the full text of this chapter or article.
Elgaronline requires a subscription or purchase to access the full text of books or journals. Please login through your library system or with your personal username and password on the homepage.
Non-subscribers can freely search the site, view abstracts/ extracts and download selected front matter and introductory chapters for personal use.
Your library may not have purchased all subject areas. If you are authenticated and think you should have access to this title, please contact your librarian.