title: Assessment of technological level of stem cell research using principal component analysis.
abstract: BACKGROUND
  In general, technological levels have been assessed based on specialist's opinion through the methods such as Delphi. But in such cases, results could be significantly biased per study design and individual expert.
  
  
  RESULTS
  In this study, therefore scientific literatures and patents were selected by means of analytic indexes for statistic approach and technical assessment of stem cell fields. The analytic indexes, numbers and impact indexes of scientific literatures and patents, were weighted based on principal component analysis, and then, were summated into the single value. Technological obsolescence was calculated through the cited half-life of patents issued by the United States Patents and Trademark Office and was reflected in technological level assessment. As results, ranks of each nation's in reference to the technology level were rated by the proposed method. Furthermore we were able to evaluate strengthens and weaknesses thereof.
  
  
  CONCLUSIONS
  Although our empirical research presents faithful results, in the further study, there is a need to compare the existing methods and the suggested method.
authors.affiliation: Science and Technology Management Policy, University of Science and Technology, Daejeon, 305-350 Republic of Korea.
authors.forename: Sung
authors.initials: S
authors.lastname: Do Cho
authors.affiliation: Department of Business Consulting, Graduate School, Daejeon University, Daejeon, 300-716 Republic of Korea.
authors.forename: Byung
authors.initials: B
authors.lastname: Hwan Hyun
authors.affiliation: School of Human Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 USA.
authors.forename: Jae Kyeom
authors.initials: JK
authors.lastname: Kim
keywords: Analysis of scientific literatures and patents; Principal component analysis; Stem cell; Technology level assessment