文档介绍：Econometrica, Vol. 76, No. 6 (November, 2008), 1317–1373
AN EMPIRICAL MODEL OF GROWTH
THROUGH PRODUCT INNOVATION
BY RASMUS LENTZ AND DALE T. M ORTENSEN1
Productivity differences across firms are large and persistent, but the evidence for
worker reallocation as an important source of aggregate productivity growth is mixed.
The purpose of this paper is to estimate the structure of an equilibrium model of growth
through innovation designed to identify and quantify the role of resource reallocation
in the growth process. The model is a version of the Schumpeterian theory of firm
evolution and growth developed by Klette and Kortum (2004) extended to allow for
firm heterogeneity. The data set is a panel of Danish firms that includes information on
value added, employment, and wages. The model’s fit is good. The estimated model im-
plies that more productive firms in each cohort grow faster and consequently crowd out
less productive firms in steady state. This selection effect accounts for 53% of aggregate
growth in the estimated version of the model.
KEYWORDS: Labor productivity growth, worker reallocation, firm dynamics, firm
panel data estimation.
1. INTRODUCTION
IN THEIR REVIEW ARTICLE of empirical productivity studies based on longi-
tudinal plant and firm data, Bartelsman and Doms (2000) concluded that the
extent of dispersion in productivity across production units, firms or establish-
ments, is large. Furthermore, the productivity rank of any unit in the distri-
bution is highly persistent. Although the explanations for firm heterogeneity
in productivity are not fully understood, economic principles dictate that its
presence will induce the reallocation of resources from less to more profitable
firms.
In this paper, we quantify the effects of worker reallocation on productiv-
ity growth. Our model is a richer version of that studied in an earlier paper
(Lentz and Mortensen (2005)), where we established the existence of a gen-
eral e