Are patent offices substitutes?

This paper evaluates whether and to what extent search and examination processes at patent offices are substitutes. Based on an original dataset comprising 4.884 patents filed simultaneously in Japan, the USA and Europe, the empirical analysis confirms that the degree of substitution is significant within the PCT framework. When patent offices have access to the search for prior art of other offices, they search into less technology classes, send fewer communications, or rely more on international citations. They also cite 12 % to 32 % less prior art. Further substitution could still be achieved, as 8 % to 27 % of remaining backward citations are duplicates -voluntarily or not - of prior work. Taken together, work reductions and overlaps witness a degree of substitution of about 37 % between the three patent offices. •The paper investigates to what extent search and examination processes at patent offices are substitutes•The empirical analysis relies on a unique dataset of 4.884 patents filed simultaneously in Japan, the USA and Europe•Having access to the search report of other offices allows to search into less technology classes and cite 12 to 32% less prior art•Work reductions and overlaps witness a degree of substitution of about 37% between the three patent offices.