title: Opinion leaders and changes over time: a survey.
abstract: BACKGROUND
  Opinion leaders represent one way to disseminate new knowledge and influence the practice behaviors of physicians. This study explored the stability of opinion leaders over time, whether opinion leaders were polymorphic (i.e., influencing multiple practice areas) or monomorphic (i.e., influencing one practice area), and reach of opinion leaders in their local network.
  
  
  METHODS
  We surveyed surgeons and pathologists in Ontario to identify opinion leaders for colorectal cancer in 2003 and 2005 and to identify opinion leaders for breast cancer in 2005. We explored whether opinion leaders for colorectal cancer identified in 2003 were re-identified in 2005. We examined whether opinion leaders were considered polymorphic (nominated in 2005 as opinion leaders for both colorectal and breast cancer) or monomorphic (nominated in 2005 for only one condition). Social-network mapping was used to identify the number of local colleagues identifying opinion leaders.
  
  
  RESULTS
  Response rates for surgeons were 41% (2003) and 40% (2005); response rates for pathologists were 42% (2003) and 37% (2005). Four (25%) of the surgical opinion leaders identified in 2003 for colorectal cancer were re-identified in 2005. No pathology opinion leaders for colorectal cancer were identified in both 2003 and 2005. Only 29% of surgical opinion leaders and 17% of pathology opinion leaders identified in the 2005 survey were considered influential for both colorectal cancer and breast cancer. Social-network mapping revealed that only a limited number of general surgeons (12%) or pathologists (7%) were connected to the social networks of identified opinion leaders.
  
  
  CONCLUSIONS
  Opinion leaders identified in this study were not stable over a two-year time period and generally appear to be monomorphic, with clearly demarcated areas of expertise and limited spheres of influence. These findings may limit the practicability of routinely using opinion leaders to influence practice.
authors: Institute of Dermatology and Plastic Surgery, Cleveland Clinic, Cleveland, OH, USA. Doumitg@ccf.org
authors: Gaby
authors: G
authors: Doumit
authors: Frances C
authors: FC
authors: Wright
authors: Ian D
authors: ID
authors: Graham
authors: Andrew
authors: A
authors: Smith
authors: Jeremy
authors: J
authors: Grimshaw
mesh_terms: D001291:Attitude of Health Personnel; D001943:Breast Neoplasms; D015179:Colorectal Neoplasms; D003625:Data Collection; D005260:Female; D013502:General Surgery / Q000458:organization & administration / Q000592:standards; D006801:Humans; D007857:Leadership; D008297:Male; D008495:Medical Oncology / Q000458:organization & administration / Q000592:standards; D008875:Middle Aged; D009864:Ontario; D010338:Pathology, Clinical / Q000458:organization & administration / Q000592:standards; D010820:Physicians / Q000458:organization & administration / Q000523:psychology / Q000592:standards; D060756:Social Networking; D013997:Time Factors