The paper investigates the patterns of persistence of innovation and of the properties of firms' knowledge base (KB) across a sample of Italian firms in the period 1998-2006. The analysis draws upon a theoretical representation of knowledge as a collective good, stemming from the recombination of knowledge bits that are fragmented and dispersed across economic agents. On this basis, we derived properties of the KB like the coherence, the cognitive distance and the variety, and investigated their patterns of persistence over time. The empirical analysis is implemented by exploring the autocorrelation structure of such properties within a quantile regression framework. The results suggest that the properties of knowledge are featured by somewhat peculiar patterns as compared to knowledge stock, and that such evidence is also heterogeneous across firms in different quantiles.
