We show the effects of Bertrand and Cournot competition on R&D investmentand social welfare in a duopoly with R …&D competition where success in R&D isprobabilistic. We show that R&D investments are higher under Bertrand (Cournot)competition when … Cournot competition can generate highersocial welfare in absence of knowledge spillover and this happens if R&D is drastic …

-tournament R&D competition. We consider thatsuccess in R&D is uncertain. We show that whether firms invest more under … Cournotcompetition or Bertrand competition is ambiguous and depends on the probability ofsuccess in R&D but does not depend on the degree … of product differentiation. While‘static’ welfare is higher under Bertrand competition, we find that ‘dynamic’ welfare …