In an era of increasing global competition and an increased interest in global clinical studies Japan has been concerned with the risk of losing its attractiveness due to perceived longer execution times and higher cost structure. In contrast, other Asian countries particularly China and Singapore are widely recognized as potential key centers for fast conduction of global clinical studies. We conducted a case comparison based on two clinical studies performed by a multinational pharmaceutical company in order to measure the productivity of clinical studies by region and country. We focused on the site-related study cost which constituted the largest portion of the cost breakdown and also impacted both time and quality management. For investigation of the productivity we propose a breakdown model with two Key Performance Indicators (KPIs), enrollment efficiency and site-related cost efficiency, for the comparison of the number of enrolled subject per site and cost, respectively. Through the comparative analysis we found that the Asian countries (excluding Japan) on average achieved higher efficiency than Japan in both indicators. In the Asian group, China and Singapore stood out as the most efficient on both speed and site-related cost. However, when the site-related cost efficiency was adjusted for Purchasing Power Parity (PPP) the cost advantage in China disappeared, implying the price level was critical for productivity management. Although quality aspects remain to be investigated we postulate that introducing a comparative approach based on a productivity framework would be useful for an accurate productivity comparison.