Post-normal science is a philosophical framework which argues that when normal science cannot predict future consequences with any degree of certainty and decisions with a strong social and political dimension need to be made, i.e. when facts are uncertain and decisions urgent, then using an extended peer community of affected stakeholders to review and ‘quality assure’ the facts and help develop a consensus way forward leads to more accurate and robust scientific decision-making.
Post normal science argues that 'normal' science works best when the uncertainty is limited and the importance of the decision is low. In such contexts the 'technical' uncertainty is reduced by using statistics. When uncertainty is greater and the decision stakes higher then professional judgement and consensus are used to reduce the uncertainty (alongside statistics). However, in contexts with high uncertainty and high decision stakes statistics and professional consensus are not enough. In these situations creating a larger peer review community made up of both professionals and lay people is also needed to 'quality assure' and enhance the accuracy and robustness of the predictions, judgements and decisions made.
What are the implications of this for HIA practice?
HIA involves the prediction of health and wellbeing impacts of a diverse group of individuals and communities, via compex pathways and over long periods of time. This high uncertainty is often married to high stakes local and regional or national decision-making e.g. the siting of waste and major other facilities.
The primary goal of community engagement in HIA is therefore less about consulting, involving or empowering (though these are important objectives in themselves) and more about uncovering the localised experiential knowledge base that communities have about both the existing negative impacts in their neighbourhoods and the potential impacts that might emerge if a proposed plan, programme or project is implemented.
Communities have valuable experiential knowledge about how their comunities work and how projects and plans have fared in the past that is crucial to gaining a holistic understanding of the potential health and wellbeing impacts. However, it is not enough or scientifcally acceptable just to ask communities about what they would like and what they think the positive and negative health impacts might be of a plan or project; but also - and more importantly - why they think so and what evidence they have that what they say is likely to happen.
HIA practitioners need to weigh up and evaluate this community evidence and assess its worth just as they would do with any other form of evidence. Who is saying what and why, how long have they lived in the area, do they cite examples and provide evidence that can be verified through other sources, how much agreement and disagreement is their between individual members of a community and on what issues.
Community evidence can therefore be critically reviewed in much the same way that other scientific evidence is reviewed and evidence review structures need to be developed to accommodate this kind of evidence. Post-normal science provides the foundations for developing such structures and processes.
Post-normal science makes it scientifcally possible to incorporate community experiential knowledge into the HIA process and provide justification for the importance of community knowledge and how this knowledge makes impact assessments more robust, rigourous and relevant.