In this paper we consider the properties of a simple test of parameter restrictions based on standard two-step efficient GMM estimators. The test is computed simply as the difference between the minimised values of the GMM criterion function in the restricted and unrestricted models. We compare...

There has much recent academic and policy interest in the issue of spatial clustering of economic activity, with most attention paid to the geographic concentration of high-tech industries. This paper describes patterns of geographic and industrial concentration in UK production industries at...