title: Measuring Health Information Dissemination and Identifying Target Interest Communities on Twitter: Methods Development and Case Study of the @SafetyMD Network.
abstract: BACKGROUND
  Little is known about the ability of individual stakeholder groups to achieve health information dissemination goals through Twitter.
  
  
  OBJECTIVE
  This study aimed to develop and apply methods for the systematic evaluation and optimization of health information dissemination by stakeholders through Twitter.
  
  
  METHODS
  Tweet content from 1790 followers of @SafetyMD (July-November 2012) was examined. User emphasis, a new indicator of Twitter information dissemination, was defined and applied to retweets across two levels of retweeters originating from @SafetyMD. User interest clusters were identified based on principal component analysis (PCA) and hierarchical cluster analysis (HCA) of a random sample of 170 followers.
  
  
  RESULTS
  User emphasis of keywords remained across levels but decreased by 9.5 percentage points. PCA and HCA identified 12 statistically unique clusters of followers within the @SafetyMD Twitter network.
  
  
  CONCLUSIONS
  This study is one of the first to develop methods for use by stakeholders to evaluate and optimize their use of Twitter to disseminate health information. Our new methods provide preliminary evidence that individual stakeholders can evaluate the effectiveness of health information dissemination and create content-specific clusters for more specific targeted messaging.
authors.affiliation: Center for Injury Research and Prevention, Children's Hospital of Philadelphia, Philadelphia, PA, United States.
authors.forename: Venk
authors.identifier: http://orcid.org/0000-0001-9603-2469
authors.initials: V
authors.lastname: Kandadai
authors.forename: Haodong
authors.identifier: http://orcid.org/0000-0001-5350-9570
authors.initials: H
authors.lastname: Yang
authors.forename: Ling
authors.identifier: http://orcid.org/0000-0001-5175-6615
authors.initials: L
authors.lastname: Jiang
authors.forename: Christopher C
authors.identifier: http://orcid.org/0000-0001-5463-6926
authors.initials: CC
authors.lastname: Yang
authors.forename: Linda
authors.identifier: http://orcid.org/0000-0002-6911-0756
authors.initials: L
authors.lastname: Fleisher
authors.forename: Flaura Koplin
authors.identifier: http://orcid.org/0000-0002-2811-4160
authors.initials: FK
authors.lastname: Winston
keywords: Twitter; digital health; dissemination; health communication; health information