£20,000 is England’s answer to the above question – this is the threshold price for a year of healthy life according to NICE. This threshold willingness-to-pay (WTP) is based on the concept of the opportunity cost – the value of the treatment that the index intervention should supplant because it is the next best use of money in terms of health benefit per unit cost. The WTP threshold has been the subject of much investigation in England and remains controversial.

The threshold for low- and middle-income countries (LMICs) is also the subject of much discussion and is usually based on mean per capita GDP – for instance the World Bank states that a healthy life year should be valued at the per capita GDP to be highly cost-effective, or three times the per capita GDP to be cost-effective.[1]

A recent article considers methods to determine thresholds for cost-effective interventions [2]; the WTP threshold described above, benchmarking against an intervention already adopted and league tables. Benchmarks invert the logic – they say if it is used, then it is cost-effective. However, health economics is supposed to be normative, and say that if it is cost-effective, then it should be used.

So we can eliminate benchmarks as a credible method, leaving the WTP threshold and league tables in contention. The problem with the latter is that the relative payback of an intervention varies materially across countries. However, it is based on the realism that budgets are limited and ephemeral, and league tables have been constructed for reference purposes, notably the WHO-Choice list [3] and the Tufts cost-effectiveness registry.[4]

The CLAHRC WM Director’s view is that both the WTP threshold and the league table approach have advantages and disadvantages. So, if you have been to all the trouble to calculate an ICER (Incremental Cost-Effectiveness Ratio), then why not use both methods; compare your results with a threshold and also see how the result compares with alternative interventions in a league table?

-- Richard Lilford, CLAHRC WM Director

Until reading this paper [1] the CLAHRC WM Director was not aware that history has become such a statistical/epidemiological subject.

Now it is known (for example from Paul Collier’s popular books) that conflict in Africa is correlated with: 1) mineral resources to be extracted; 2) weak political institutions; 3) ethnic fragmentation; and 4) endemic poverty. In the latter example, the direction of causality is far from clear. Colonial map drawers must bear plenty of responsibility for 3), and more arguably 2). But the colonial period was really rather brief; what about a legacy from the more distant past? Well, Besley and Reynal-Querol obtained data on all historical conflicts in Sub-Saharan Africa documented to have occurred between 1400 and 1700. They found that areas with high rates of conflict in this epoch have statistically increased rates of post-colonial conflict compared to areas with lower rates of pre-colonial conflict. The high conflict areas are associated with lower levels of trust, stronger senses of ethnic identity, and lower economic development. Quite how memory is propagated back to the period before Queen Anne sat on the British throne is a mystery to the CLAHRC WM Director. The article is full of statistical tables and algebra, and this was as fascinating as the subject matter.

-- Richard Lilford, CLAHRC WM Director

Leave a comment

Return to top

Wendy Robertson

Dr Wendy Robertson is an Associate Professor in Public Health at Warwick Medical School, and works on CLAHRC WM Theme 3, Prevention and Detection of Disease. Her research interests are broadly in the areas of health promotion and health protection. She has just completed an RCT of a parenting intervention for the treatment of childhood obesity, “Families for Health”, comparing this with usual care in three sites across the West Midlands. She also helped to organise the conference on the 2nd July 2015 on childhood obesity for CLAHRC, in collaboration with Public Health England West Midlands. Other areas of interest include obesity in pregnancy and the methods for monitoring physical activity. In the area of health protection, she was involved with the investigation of a large outbreak of occupational respiratory disease at a factory that worked with metal working fluid within the West Midlands, and has maintained a research interest in this area.
 
Wendy graduated in Sports Science & Physical Education from the University of Loughborough (1983), has a Masters in Public Health from the University of Birmingham (2002), and a PhD from the University of Warwick (2010). Her NHS career started in 1985 as a Clinical Scientist at Birmingham Heartlands Hospital. In 1992 she was appointed as a Health Promotion Specialist (No Smoking Co-ordinator) with Solihull Healthcare NHS Trust. In 2000 she became a Specialist Trainee in Public Health within the West Midlands Deanery, completing public health training in 2006. She is on the UK Public Health Register and was elected a Fellow of the Faculty of Public Health in 2006.

Return to top

Re: Where is the Philosophy of Science in Research Methodology?

-- Russell Mannion

I couldn't agree more with you, Richard, philosophy of science is hugely important to scientists. It helps them to uncover assumptions that inevitably underlie their work and provides them with a language and concepts to critically discuss them. In my view, Helen Longino's 'Science as Social Knowledge, Values and Objectivity in Scientific Inquiry' (1990) addresses these issues in an accessible and balanced way. However, this does not seem to be the received view, as observed by Susan Haack (another good read!), stating that 'philosophy of science is generally regarded to be as relevant to scientists as ornithology to birds' (original source unknown to me).

On the positive side, it might interest you to know that one of the great physicists of our time, Mikhail Katsnelson, IS interested in philosophy of science AND has actualy written about it. He does all of these things along with writing poetry. 
-- Gert Jan van der Wilt

Dear Richard
Thank you for this stimulating piece. Applied health research often appears to lack any underlying philosophical basis and I believe this is one reason why it is a) rather unattractive to some of the most able early career researchers and b) often appears as little more than an aggregration of ‘interesting facts’. I welcome your voice but would dispute your characterisation as a ‘lonely’ voice; there is at least one other.
-- Isabel Clare

I cannot resist starting this with a quote form Bertrand Russell that I recently had the pleasure of discussing with Richard. "The British are distinguished among the nations of modern Europe, on the one hand by the excellence of their philosophers, and on the other by their contempt for philosophy. In both respects they show their wisdom." [In: ‘Philosophy and Politics’; Unpopular Essays (Unwin Paperbacks, London 1984) p. 13.]

When I was young and gauche and studying physics in Cambridge (in about 1970) I had a friend called David Papineau who organized a debate  between (I think) Sir Martin Rees and a philosopher, whose name I forget, on the topic of "Schrodingers Cat". Believing that understanding the philosophy of science would make me a better physicist I went along with enthusiasm. What has remained with me is this. The philosopher spoke first and handed each of us a printed copy of his talk which he then proceeded to read out. Rees then stood up, without notes but with a piece of chalk, waved his hands around a lot, scribbled bits and pieces on the blackboard and then sat down. Later that week I happened to sit next to Rees at lunch in Kings and I asked him about this, to me, rather strange encounter. His answer was that there is so much that is completely agreed on in physics that we can argue and discuss it all in a very loose and unstructured way. On the other hand there is so little that is agreed on in philosophy that every word has to be chosen with care and defended to the death.

So the first problem might just be that we have drifted so far apart in our language and rules of engagement that it is hard to to talk to each other any more. The second problem is that while I still love the idea of teaching young people the philosophical underpinnings of their science I fear that they spend so much time looking after their Twitter, Facebook and e-mail accounts that they no longer have time to reflect on anything. But perhaps the best answer I ever had was one evening, having a somewhat drunken and totally uninformed argument with a friend who was studying philosophy, I asked him: What possible point can there be to studying philosophy? To which he immediately replied: So that we can have argument like this.
-- Brian Williams

Readers may want to look at the following paper published in Social Science and Medicine by Currie et al 2014 to understand why clinician scientists and those of a more sociological origin face challenges in mediating the epistemological divide in the CLAHRC initiative  -- Currie G, El Enany N, Lockett A. Intra-professional dynamics in translational health research: The perspective of social scientists. Soc Sci Med. 2014;114(1): 81-8.
-- Graeme Currie

It was interestingly commented by a philosophy expert that her role was rather similar to that of an expert on drains. No-one bothers to think about them except in the rare time where things go radically wrong
-- Rupert Fawdry

Re: Ranking Hospitals on Preventable Deaths