title: Research design in end-of-life research: state of science.
abstract: OBJECTIVE
  The volume of research on end-of-life care, death, and dying has exploded during the past decade. This article reviews the conceptual and methodological adequacy of end-of-life research to date, focusing on limitations of research to date and ways of improving future research.
  
  
  METHODS
  A systematic search was conducted to identify the base of end-of-life research. Approximately 400 empirical articles were identified and are the basis of this review.
  
  
  RESULTS
  Although much has been learned from research to date, limitations in the knowledge base are substantial. The most fundamental problems identified are conceptual and include failure to define dying; neglect of the distinctions among quality of life, quality of death, and quality of end-of-life care. Methodologically, the single greatest problem is the lack of longitudinal studies that cover more than the time period immediately before death.
  
  
  CONCLUSIONS
  Gaps in the research base include insufficient attention to psychological and spiritual issues, the prevalence of psychiatric disorder and the effectiveness of the treatment of such disorders among dying persons, provider and health system variables, social and cultural diversity, and the effects of comorbidity on trajectories of dying.
authors.affiliation: Department of Sociology, Institute for Care at the End of Life, Duke University, Durham, NC 27708, USA. lkg@geri.duke.edu
authors.forename: Linda K
authors.initials: LK
authors.lastname: George
mesh_terms: D003625:Data Collection / Q000379:methods; D003627:Data Interpretation, Statistical; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000379:methods*; D012107:Research Design; D013727:Terminal Care