"Is health impact assessment a science?I agree with every part of this quote except the phrase "HIA is not strictly a science" because for me it describes perfectly what it means to apply scientific knowledge to the real world outside the lab.
It is important to emphasise that HIA is not strictly a science.
Having said this, it most certainly draws on a scientific knowledge base.
Scientific evidence on health impacts of specific determinants forms the backbone of this creative, interdisciplinary form of enquiry.
But each HIA is uniquely located in time, space and local conditions though its evidence base can be evaluated, and the rigour with which procedures and methods were implemented can (and should) be assessed.
Uncertainties encountered during the undertaking of HIAs will frequently dictate the need to make assumptions, which may result in challenges to the HIA’s validity: such assumptions are acceptable as long as they are stated explicitly, so that the reader is free to agree or disagree. ”
For me, both HIA and science in all its myriad forms are "interdisciplinary forms of enquiry"; to misquote John Donne 'No science is an island entire unto itself every science is a piece of the continent, a part of the main'.
HIA for me is:
1. a systematic endeavour;
2. it uses knowledge and methods from other scientific disciplines e.g. epidemiology, sociology, toxicology and biology;
3. it aims for rigour,
4. it actively avoids bias and confounding;
5. the findings of one HIA have some applicability to communities of a similar social and cultural mix as that studied by the HIA; and
6. its results are subject to revision when new evidence or information comes to light that contradicts and refutes previous knowledge.
For me, this quote illustrates a misreading of science as about numbers and quantitative findings and about universal laws that transcend time and space. That works for the physical world (most of the time) but doesn't work so well for our social and cultural worlds where general laws and theories need to take account of local context. In fact even the universal laws of physics have to take account of local context. Science is about systematic enquiry where the resulting knowledge is always provional and subject to revision.
What's even more interesting is that environmental impact assessment practitioners don't have any qualms about calling EIA a science. Neither do economists or sociologists.
But public health professionals and HIA practitioners, in my experience, seem to have a problem with saying that HIA is a public health science? Or maybe I've got it wrong?
I tend to agree with Martin's comments about HIA not being science per se - issues around the reproducability and generalisability of findings can be tricky. I like to think of HIA as being about the use of information, rather than the creation of it. The fact that EIA (like HIA) often involves collecting/researching new contextually-specific information may make it seem more like "science" than it is.
ReplyDeleteThat being said, the observer effect has cast doubt on many claims that it's possible to observe a range of phenomena without changing the outcome. The obvious difference is that HIA explicitly aims to change what happens.
I agree with Salim on this and think epistemic differences (ie realist/ constructivist debates) are core to this discussion. By ignoring the socially constructed nature of 'science' we risk HIA being forever doomed to produce only instrumentally justifiable knowledge.
ReplyDeleteOntological relativism suggests that multiple social realities are products of human intellect therefore knowledge can be categorised as an outcome of what we view as cause and effect, with truth an emergent property of that knowledge. This reflects a linear relationship between cause and effect.
Truth claims of causal statements require three conditions to prevail:
• firstly variable A precedes variable B,
• secondly there exists a relationship between A and B (ie as measures of A change, measures of B also change), and
• thirdly there is no other variable C responsible for the change.
This is claimed possible in experimental research designs (described as closed systems) by controlling variables. However, the social world is described as an open system. In open systems, causes are dynamic not static. The relationship between the elements is the 'thing' that makes something a cause or an effect and this may change with context.
The importance of context, the environment, and the system(s) of influence that surround them, illuminate the 'reality' of the social world as dynamic, messy and complex. Therefore simple cause-effect explanations are simplistic at best and may reflect or reinforce dominant pre-existing models of the best way we can know the social world at worst. A strength of HIA methodology (in my opinion) is its usefulness in moving beyond traditional views of causal laws (as in some natural sciences) to causal principles embracing the concepts of time and notions of causality.
To avoid being misled as to the validity of 'truth claims'. I think approaches that include a high degree of reflexivity offering alternative explanations thus making explicit inherent contradictions and acknowledging a 'crisis of representation' would bridge this qual/quant divide. For example reflexive accounts in longitudinal data analysis (LDA) draw attention to the practical choices made by the researcher, in data collection and analysis in particular. These enable the reader to judge the quality of the research, validity and trustworthiness of the conclusions drawn. This is often missing in HIA reports although this may have been discussed with steering group members.
HIA typically draws on different types of knowledge (evidence). To know something is to be or feel certain of the truth or accuracy of something, to understand, experience or perceive of truth. Truth in English means straight, honest, faithful, a verifiable fact. Two issues here, firstly knowledge is always subject to tests for coherence whether that knowledge is generated via natural scientific methods or social scientific methods. Secondly, the concept of truth is not clear cut. 'Truth' is something constantly being negotiated redefined and reconstituted as we learn to see things differently and create new words to name and categorise things.
If social science is an instrument of social problem solving – which I believe it is - and HIA falls into this category – which I think it does, then understanding the realist /constructivist debate is at the core of identifying the public role of HIA and facilitate understanding as to the relationship between 'science' and other forms of knowledge.
This leads me to your last point (maybe?). It seems reasonable to assume that the positioning of public health reflects the dominant paradigm within which it functions...
I'd like to take up Martin and Ben's points first before adding onto what Debbie has said.
ReplyDeleteHIA is predictive and its findings are verifiable. Here's why, HIA uses public health evidence to say, for example, that greenspace is good for individuals and communities at a number of levels and asks for this to be taken into account when, again for example, the developer of a new housing development attempts to reduce existing greenspace and or build no greenspace within their development. HIA predicts that on balance all things being equal - which as Debbie correctly points out rarely happens in the real world - losing or not building greenspace into the new development will tend to have negative physical, emotional and social health and wellbeing impacts. The size of this impact on individuals is likely to be small but the cumulative impacts on the community as a whole over time can be considerable. This is especially so where the loss of greenspace leads to further losses because the new development sets a precedence for future developments. This HIA prediction can be tested by undertaking monitoring and evaluation studies after the new development is built to assess the degree to which any negative health and wellbeing impact have occurred because of the loss of the greenspace. The fact that commissioners and clients of HIA rarely provide the funds to carry out in-depth evaluation or monitoring is not the fault of HIA.
I will leave Debbie to explain what her perspective is but I agree with most of what she has said. We deal with both complex and dynamic influences in the social world that directly and indirectly affect health and wellbeing. Unpicking what exactly has increased or decreased health is difficult but not impossible. It requires us to be more humble and go back to working out each causal step in a pathway of action. We have not, and from my perspective, have yet to do this work within HIA. We tend to leave it to others, see ‘Neighbourhoods and Health’ as well as ‘Social Epidemiology’ edited by Ichiro Kawachi and Lisa F. Berkman. While Social Epidemiology can give us the tools to make HIA more predictive we need Lay Epidemiology, to do what Debbie is calling for, to help us face the fact that when we apply scientific knowledge in the social world it isn't enough. We never have the amount of evidence, data and understanding to make mathematically precise judgements about cause and effect. That's where communities can feed in their experiential knowledge about how the social world they live in works and inform policy and decision-makers what values and principles are important to them in the context of a new plan or development. Finally, sociology and anthropology can help HIA to understand that policy and decision-making are not rational scientific processes they are messy, conflicting and value-laden enterprises just like HIA itself and all other sciences.
Martin makes a very important point. I think the 'counterfactuality' effect of HIA makes HIA a process as much as an outcome. By intervening through HIA we are changing the outcome but while we cannot verify within an individual project we can verify a set of similar projects.
ReplyDeleteHowever, there is a work around. Taking our example of a new housing development and greenspace. Of the set of these types of developments, that have undergone HIA, there are three broad outcomes: that all the HIAs recommendations have been taken into account; some of them have been taken into account; and none of them have been taken into account.
HIA theory predicts that, all other things being equal,:
A. Of the developments where all the HIAs recommendations were taken into account, and the developments design and operation modified accordingly, the health impacts on new and existing communities should be positive overall. There may be changes in the distribution of positive and negative effects but overall the health benefits will far outweigh the costs.
B. Of the developments where only some of the main recommendations were taken into account, the health impacts should be slightly positive or neutral overall (at a minimum).
C. And of the developments where none of the recommendations were taken into account (and this does happen), the health impacts should be negative overall (or neutral at best).
In practice, this kind of evaluation would be very difficult and very expensive but not impossible. This kind of meta-evaluation built on individual project HIA evaluations would provide verification not only of the negative health impact predictions of HIA should recommendations not be taken up but also of the predictions of positive health impacts for when recommendations are taken up.
The Medical Research Council in the UK is already doing 'natural' experiments using a similar research philosophy to study health impacts. It is studying two similar sets of communities: one where a development is going to take place and one where it isn't. By following these two communities they aim to find what the health impacts are of the development over time.
A similar approach to developments that have undergone and not undergone HIAs can be undertaken of which a subset of evaluation would be the one I described earlier.
Finally, I agree with Martin, HIA is a process but, for me, it is a at its heart a strongly scientific one. To stretch the point, HIA has a scientific process that uses scientific methods to produce scientific outcomes that can be scientifically evaluated/verified.