The paper studies the degree of homogeneity of innovative behavior in order to determine empirically an industry classi¯cation of Dutch manufacturing that can be used for policy purposes. We use a two-limit tobit model with sample selection, which explains the decisions by business enterprises...

This paper explores the aggregation problem and illustrates its relevance using data for the Netherlands from the third Community Innovation Survey (CIS3), and production and financial statistics. It compares the results of an innovation output equation that was estimated using data on...