title: The evolution of social networks through the implementation of evidence-informed decision-making interventions: a longitudinal analysis of three public health units in Canada.
abstract: BACKGROUND
  We studied the evolution of information-seeking networks over a 2-year period during which an organization-wide intervention was implemented to promote evidence-informed decision-making (EIDM) in three public health units in Ontario, Canada. We tested whether engagement of staff in the intervention and their EIDM behavior were associated with being chosen as information source and how the trend of inter-divisional communications and the dominance of experts evolved over time.
  
  
  METHODS
  Local managers at each health unit selected a group of staff to get engage in Knowledge Broker-led workshops and development of evidence summaries to address local public health problems. The staff were invited to answer three online surveys (at baseline and two annual follow-ups) including name generator questions eliciting the list of the staff they would turn to for help integrating research evidence into practice. We used stochastic actor-oriented modeling to study the evolution of networks. We tested the effect of engagement in the intervention, EIDM behavior scores, organizational divisions, and structural dynamics of social networks on the tendency of staff to select information sources, and the change in its trend between year 1 and year 2 of follow-up.
  
  
  RESULTS
  In all the three health units, and especially in the two units with higher levels of engagement in the intervention, the network evolved towards a more centralized structure, with an increasing significance of already central staff. The staff showed greater tendencies to seek information from peers with higher EIDM behavior scores. In the public health unit that had highest engagement and stronger leadership support, the engaged staff became more central. In all public health units, the engaged staff showed an increasing tendency towards forming clusters. The staff in the three public health units showed a tendency towards limiting their connections within their divisions.
  
  
  CONCLUSIONS
  The longitudinal analysis provided us with a means to study the microstructural changes in public health units, clues to the sustainability of the implementation. The hierarchical transformation of networks towards experts and formation of clusters among staff who were engaged in the intervention show how implementing organizational interventions to promote EIDM may affect the knowledge flow and distribution in health care communities, which may lead to unanticipated consequences.
authors.affiliation: Health Research Methodology Program, Faculty of Health Sciences, McMaster University, Hamilton, Canada. yousefr@mcmaster.ca.|, 175 Longwood Road South, Suite 210a, Hamilton, ON, L8P 0A1, Canada. yousefr@mcmaster.ca.
authors.forename: Reza
authors.initials: R
authors.lastname: Yousefi-Nooraie
authors.affiliation: School of Nursing and Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada. dobbinsm@mcmaster.ca.
authors.forename: Maureen
authors.initials: M
authors.lastname: Dobbins
authors.affiliation: Department of Sociology, University of Toronto, Toronto, Canada. alexandra.marin@gmail.com.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Marin
authors.affiliation: Department of Sociology, College of Humanities, Arts, and Social Sciences, University of California, Riverside, USA. robert.hanneman@ucr.edu.
authors.forename: Robert
authors.initials: R
authors.lastname: Hanneman
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada. lohfeld@mcmaster.ca.
authors.forename: Lynne
authors.initials: L
authors.lastname: Lohfeld
mesh_terms: D003142:Communication; D003657:Decision Making; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008297:Male; D009864:Ontario; D011635:Public Health Administration / Q000379:methods*; D012944:Social Support; D013269:Stochastic Processes; D057170:Translational Research, Biomedical / Q000379:methods*