Evidence-based health policy: context and utilisation
Introduction
Over the last decade we have observed an explosion in both the availability and accessibility of information. With this, we have seen greater recognition of, and attention given to, the classic economic dilemma between the scarcity of resources and our potentially unlimited wants, raising difficult resource allocation, rationing and priority setting questions. Greater demand has been placed on decision-makers at all levels and in all fields to justify their decisions in response to this dilemma. Decisions are becoming more transparent, shifting from implicit to explicit methods of decision-making (Coast, Donovan, & Frankel, 1996). Evidence-based decision-making has been proffered as a means to address this growing demand for explicitly justified decisions.
The field of medicine has embraced these movements with the development of evidence-based medicine (EBM) (Evidence-Based Medicine Working Group, 1992), defined as ‘…the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients’ (Sackett, Rosenberg, Grover, Haynes, & Richardson, 1996). While focusing on the individual-clinical level, proponents of the EBM model have advanced a scientific conception of evidence—evidence developed through systematic and methodologically rigorous clinical research, emphasising the use of science while de-emphasising the use of intuition, unsystematic clinical experience, patient and professional values, and pathophysiologic rationale (Evidence-Based Medicine Working Group, 1992). Critics of EBM have suggested that a scientific conception of evidence is too narrow, neglecting a more expansive range of evidentiary sources relevant to clinical decision-making (Buetow & Kenealy, 2000; Miles et al., 2000). While proponents of EBM have recognised that scientific evidence, by itself, is not sufficient and needs to be integrated with other types of evidence (Haynes, Devereaux, & Guyatt, 2002; Rosenberg & Sackett, 1996), they still focus on the use of the ‘best’ sources of evidence (Sackett et al., 1996). This has led to the development of numerous hierarchies of evidence and classification criteria based largely on the sophistication of a study's design and its methodological rigour (Canadian Task Force on the Periodic Health Examination, 1994; Oxford Centre for Evidence-Based Medicine, 2001; US Preventive Services Task Force, 1996). Critics of EBM have countered that these evidence hierarchies lack their own evidence-base, imposing valuations and preferences that endeavour to constrain or limit the influence and impact of the full range of potential evidentiary sources on decision-making (Djulbegovic, Morris, & Lyman, 2000; Miles et al., 2000).
While these debates and discussions continue, EBM has grown more pervasive. Evidence-based decision-making is now garnering greater attention within the health policy environment, with peer-reviewed articles on evidence-based health policy increasingly common (Black, 2001; Harries, Elliot, & Higgins, 1999; Klein, 2000; Macintyre, Chalmers, Horton, & Smith, 2001; Niessen, Grijseels, & Rutten, 2000). But as Black (2001) stated, ‘[e]vidence-based policy is not simply an extension of EBM: it is qualitatively different’. As we move from EBM to evidence-based health policy, the decision-making context changes, shifting from the individual-clinical level to the population-policy level. Decisions are subject to greater public scrutiny and outcomes directly affect larger numbers of people, heightening the requirement for explicit justification. This shifting decision-making context highlights our current conceptual deficiencies and the limited attention given to understanding the role that context plays in influencing evidence-based decisions.
As the decision-making context shifts from the individual-clinical level to the population-policy level, should what constitutes evidence change? Should the value attributed to different types of evidence change? Should we change how we make evidence-based decisions? To address these issues, we have developed a conceptual framework for evidence-based decision-making, focusing on how context impacts on what constitutes evidence and how that evidence is utilised. We illustrate our framework through a case study of policy development for population-based colorectal cancer screening, which has been integrated throughout the major sections of the paper, to compare and contrast the similarities and differences between EBM and evidence-based health policy. Given the multidisciplinary scope of this work, our hope is that the conceptual framework will stimulate further discussion regarding the role of evidence, context and utilisation in the development of health and social policy.
Section snippets
Evidence and context
The two fundamental components of an evidence-based decision are evidence and context. Two distinct orientations towards determining what constitutes evidence are discussed, as is a basic categorisation of the ways in which the decision-making context can impact on evidence-based decision-making. Following this, the relationship between evidence and context in evidence-based decision-making is considered.
Evidence utilisation
The two fundamental components of evidence-based decision-making, evidence and context, have been addressed. However, it is the interaction between evidence and context in evidence-based decision-making that is most critical to the development of evidence-based health policy. Even when there is general agreement on what constitutes evidence, there is considerable observational work to suggest that the same evidence, utilised in different contexts, often leads to different decision outcomes (for
A conceptual framework for context-based evidence-based decision-making
Evidence utilisation includes not only the determination of what evidence is needed to make a decision, but also how the internal and external validity of individual sources of evidence are assessed and how individual sources of evidence are collectively weighted and prioritised. Both internal and external contextual factors fundamentally influence and affect what constitutes evidence and how we utilise that evidence to justify decisions. To better understand how evidence-based decisions are,
Acknowledgements
This paper was based on conceptual work done for a project supported by the Health Evidence Application and Linkages Network (HEALNet). M.D. was supported by a doctoral student fellowship from HEALNet and a doctoral training award from the Canadian Institutes of Health Research (CIHR). V.G. was the scientific program leader of HEALNet. R.E.G.U. was supported by a Research Scholarship from the Department of Family and Community Medicine, University of Toronto and by a New Investigator Award from
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