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The Emergence of Evidence-Based Policy

Evidence-based Policy

The emergence of Evidence-Based Policy

The development of evidence-based policy has its roots squarely within the field of medicine. It was following the end of World War 2 that there was a considerable uptick in interest in evidence-based interventions to guide decision making within the field of medicine. This change sought to ensure that health interventions would be based on the best available evidence. This can be seen as being in opposition to the period in medical interventions prior to this, wherein many health-based initiatives did not require a considerable empirical basis. This was due in part to the situation wherein, in most cases, simple observation would suffice in ensuring that interventions were effective. This can be seen in the cases of the development of penicillin, the considerable progress made in urban sanitation, and the refrigeration of perishable products. That these interventions consisted of the lower hanging fruits of health-based intervention, and as such, the treatment effects were patently observable, meant that evidence-based interventions were rarely required. However, following these interventions, and beginning in the 1950s onwards, the returns for many health-based interventions were increasingly marginal and there was an increased need for the application of such approaches as randomized control trials (RCTs). The use of RCT’s, for example, could be used to observe the treatment effects and to accurately capture the components of interventions that could be repeated to constitute an evidence base on which to base future interventions (Baron, 2018).

Whilst the same trajectory of the use of the framework of evidence-based interventions cannot be observed directly within the policy fields; comparisons can be drawn with a number of social and political changes. We can see within the introduction of money, which replaced the barter system, or the protection and promotion of property rights and the rule of law serving to create the conditions for economic development. The treatment effects of these interventions were often large enough to be captured through observation and as such, did not require the collection and collation of data to inform evidence-based interventions in the future (Baron, 2018). These low-hanging fruits interventions are termed as having “blockbuster effects” according to (Baron, 2018) and are considered as being able to identify the effects of interventions through observation alone.

That the world of policy sciences has increased in complexity is not a new or radical concept; however, it is this increasing complexity that has served as the basis for the increased interest in the application of evidence-based interventions. In particular, this has led to the need to observe not just the impact of an intervention, but also the cause of the change, Baron (2018) refers to this development as being based in seeking “To determine whether the intervention caused the outcomes we observe, we need an evaluation method that controls for confounding factors.” This shortfall leads to a situation wherein it is not simply possible to observe an intervention in isolation and draw conclusions as to whether the intervention was the sole contributor to the change. This has led to a need for the collection and collation of evidence to understand the effectiveness of interventions better. This rise in complexity has led to a situation wherein most policymakers now seek to adopt best practice and interpret the evidence in the context of the outcomes of policy interventions. This has however led to a situation wherein the gathering, analysis, and application of evidence requires further evaluation of the values underpinning it.

The logic surrounding evidence-based policymaking has, however, had a strong grip on policymaking in recent decades, with some authors going as far as to highlight that ‘rooting policy in evidence has all the appeal of motherhood and apple pie. The rhetoric is cheap and easy’ (Tilley and Laycock, 2000). This understanding is echoed by a number of scholars, who point towards the prominent position played by evidence-based policy, with the oft-quoted “what matters is what works,” provided by Tony Blair’s Labour Party in the UK in the 1990’s serving as a mantra on which most evidence-based policymaking is assumed to be predicated.  Whilst the logic is intrinsic in any understanding; indeed a number of scholars (Baron, 2018, Parsons, 2002) go as far as to point out that basing policy-making on evidence is an easily digestible narrative surrounding policymaking, the question of how to understand and interpret what works is the challenge inherent with evidence-based policy. This point to the broader question and one, which many scholars have sought to address (Marston and Watts, 2003; Perry, 2002) namely the question of what constitutes evidence. This particular question already begins to cast a number of challenges on this approach to policymaking. Whilst many policymakers would point towards a multitude of types of evidence as being necessary; it has largely been seen that some forms of evidence supersede and indeed matter more than others. We can see this within the work of  (Marston and Watts, 2003) who goes as far as to state that “If knowledge operates hierarchically, we begin to see that far from being a neutral concept, evidence-based policy is a powerful metaphor in shaping what forms of knowledge are considered closest to the ‘truth’ in decision-making processes and policy argument.”. That evidence can be considered to operate hierarchically will likely not come as much of a surprise to many, the values, which underpin this hierarchy, however, can cast doubt on the privileging of some strains of evidence over others. That this can constitute a value judgment on what sources will achieve certain objectives, and indeed, whether the evidence used is truly value-neutral and prioritizes “what works” serves as a key question in this article. This can be seen in (Nutley, Davies and Walter, 2002) wherein the authors note that  “in  practice, the  public  sector  in  the  United  Kingdom  relies on a limited  range  of  evidence,  specifically:  research  and  statistics,  policy evaluation, economic modeling, and expert knowledge.” This reliance on certain strands of evidence however, cannot solely be laid at the feet of lacking objectivity or advancement of particular values, but more specifically as discussed in (Perri, 2002), that the sheer scale of evidence produced, and the cognitive and time limitations on distilling good evidence from more dubious evidence provides a particular challenge to policymakers. This can also be understood in the context of quality empirical research taking a considerable length of time, a commodity that many policymakers simply lack influencing the privileging of some strains of evidence over others, and indeed challenging the premise of whether a full reliance on evidence is practical given these shortfalls. This also provides an insight into why some forms of evidence are used and prioritized over others, and indeed, why there is a considerable challenge to qualitative research factoring into many equations of what constitutes ‘evidence.’


Jason Deegan

Jason Deegan is a PhD Candidate (Stipendiat) and research fellow at the University of Stavanger. His work primarily focuses on; Innovation, Regional Studies, Smart Specialisation and Policy.

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