NATURE INDEX | SCIENCE CITIES Tsukuba Tokyo metro area metro area Nagoya London CITY LINKS metro area e top collaborating cities in Cambridge the Nature Index are located in the same country. Sendai Baltimore - Washington Leading science cities form dense networks Osaka -Kyoto Kobe - of collaboration within (Keihanshin) Chicago - their national Naperville - Elgin boundaries. This graph shows the top 25 city pairs in the Nature Index, measured by their bilateral Nanjing New York collaboration score B metro area (CS) — the sum of each city’s fractional count (FC) on papers with authors from C both cities in the 82 Philadelphia high-quality research Hefei metro area journals tracked by the index. The partners typically contribute to an A equal share of San Francisco the authorship. - San Jose Beijing A: PEAK PERFORMER Los Angeles - Long Beijing is the top Beach - Anaheim science city in the index, with an FC of Changchun 2,142.53 in 2017. Its contribution to high-quality research Boston - Cambridge - Newton has grown over the Wuhan past six years, as has Seoul Daejeon metro area that of many cities across China. Shanghai China B: DYNAMIC DUO C: TRANSNATIONAL Tokyo and the ALLIANCE Japan Keihanshin region are Change in adjusted Strength of Beijing and New York collaboration the top collaborators in are the only global city South Korea City FC 2017 FC 2012–2017 the index, contributing pair in the top 25, to a joint CS of 442.88 contributing to a joint United States in 2017. CS of 125.73 in 2017. United Kingdom Low High Falling Rising Low High GLOBAL MATCH URBAN CONNECTIONS The top ve international city pairs in the Nature Index, measured by Below are the top 10 most externally collaborative cities among the top 200 bilateral collaboration score (CS). Bars show each partner's contribution by fractional count. Some 97% of the 180 articles (AC) authored by to the collaborative papers. researchers in Donostia/San Sebastián have co-authors based outside the city. Donostia/San New York metro area 125.73 Sebastián, Spain Beijing Rome, Italy Oak Ridge, Paris metro area 110.30 United States New York metro area Köln, Germany San Francisco - San Jose Oslo, Norway 99.01 Beijing Naples, Italy Externally collaborative AC Boston - Cambridge - Newton Gent, Belgium 84.93 Beijing Bern, Switzerland London metro area Brussels, Belgium 82.69 New York metro area Milan, Italy 0 20 40 60 80 0 200 400 600 800 CS AC S8 | NATURE INDEX 2018 | SCIENCE CITIES ©2018 Spri nger Nature Li mited. All ri ghts reserved. .