摘要：We examine the “home bias” of international knowledge spillovers as measured by
the speed of patent citations (i.e. knowledge spreads slowly over international
boundaries). We present the first compelling econometric evidence that the
geographical localization of knowledge spillovers has fallen over time, as we
would expect from the dramatic fall in communication and travel costs. Our
proposed estimator controls for correlated fixed effects and censoring in
duration models and we apply it to data on over two million citations between
1975 and 1999. Home bias declines substantially when we control for fixed
effects: there is practically no home bias for the more “modern” sectors such as
pharmaceuticals and information/communication technologies
关键词：Fixed effects, home bias, patent citations, knowledge spillovers
