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Author Archives: Chris Sampson

About Chris Sampson

punk rock health economist

The potential of the super QALY to reconcile the key contentions in health economics

Economics is largely about trade-offs and compromise. Academics study the former but don’t often engage in the latter. In health economics, as in other fields, a key trade-off is between equity and efficiency. We’ve been studying this for a.very.long.time. Despite this, as Culyer has identified, equity is hardly considered in current health technology assessments. We all agree it should be, but just can’t seem to figure it out. Indeed, ihas been argued that incorporating equity concerns into cost-effectiveness analyses could still be a long time coming.

But let’s be a bit more positive. The elusive `Super QALY’, as it has been described, should come eventually. And when it does, it’ll be great! One of the reasons, I propose here, is that it has the power to reconcile many of the disagreements that currently fuel (hamper?) debate in our field. Hence, the super QALY might just allow us to get on with fussing over minutia issues of economic evaluation.

Trade-offs

There are necessary trade-offs in decisions of resource allocation. These might be described as the ‘positive’ tensions economists deal with; they relate to decisions that must be made, regardless of our values. The equity–efficiency trade-off is the main one here. But there are others. For example, health care interventions have the dual aim of increasing both the quantity and quality of an individual’s life. The QALY attempts to address this. However, the way we value quality of life also incorporates considerations of length of life in so much as ‘death’ is used in the valuation of health states. This is problematic, as has been discussed. Economists haven’t really gotten round to disagreeing about this yet, but there’s plenty else on which we disagree.

Disagreements

These might be described as ‘normative’ tensions. They concern what different economists think should and should not be done; mainly relating to the process of valuing health states. There are welfarists and non-welfarists. There are those who support societal preferences, and those who support capturing patient experience. It should be clear to most that neither side in these debates is wrong. Most health economists acknowledge the value of capturing utility as well as the importance of capabilities. Most will attach some value to society’s preferences and some to those of the individual.

A super-QALY solution

It’s never been completely clear what the ‘extra’ in extra-welfarism (as currently practiced) actually consists. The super QALY will surely formalise this; it could involve some completely non-welfarist notions. The most common idea of the super QALY is one where the current health-related QALY is weighted based on some equity considerations. So, if this is where economic evaluation is heading, we’re likely to end up with an extra step of estimating the equity impact of an intervention. But, while most studies seem to suggest that this might just be an add-on process, I think it would require a realignment of the methods we already use.

Equity analysis

There’s no need for me to reiterate the importance of equity considerations. Plainly we (economists, the public) care about needs, capabilities, opportunities and equality. How we define the equity analysis is incidental. More important is that we get on with doing it and just see what happens. There are lots of measures we could use and different approaches we could take. For arguments sake (and because I quite like it), let’s say the equity analysis is characterised by a ‘minimum capabilities‘ approach. Something similar to Daniels’s normal opportunity range. People could have the normal opportunity range, have fewer opportunities or have more opportunities. We can argue later about where the threshold lies. People below the threshold could be said to be in ‘need’. Again, argue about this later. States could be defined using a capabilities measure; let’s just say the ICECAP-A for now (though I don’t much like it). Here in the world of health economics we like 0-1 scales, so the ICECAP-A could be valued based on these anchors. So, let’s say 1 is the minimum capabilities or normal opportunity range threshold. Zero equates to being dead. Values can drop below zero where opportunity sets represent a state worse that non-existence. For the equity analysis we are not interested in utility or satisfaction, so the valuation would not be by the individual. Values could be elicited from society, possibly. The valuation technique could be a person trade-off, maybe. Or we could let ethicists come up with weightings. This framework, surely, would satisfy the non-welfarists.

Health utility analysis

I see no reason why the estimation of health benefits cannot be utility-based. Utilitarian satisfaction is sufficient if non-welfarist concerns are incorporated in an equity analysis. Personally I believe that whether this is based on experiences or preferences is largely inconsequential and that, in terms of health, most of the differences demonstrated between the 2 are a function of the elicitation methods. Therefore, utility analysis would remain largely unchanged. However, the value of 0 would change. Zero currently represents either being dead or in a health state equivalent to being dead, despite these two things not being of equivalent value to a person. Under the new framework there is no need to incorporate death into the health utility analysis, as it is accounted for in the equity analysis. 0 should represent the worst health state imaginable. There would be no negative values.

Cost-effectiveness analysis

These 2 analyses would then be combined to form a relatively routine cost-effectiveness analysis to address the efficiency of the intervention. The QALY would be calculated in the usual way, but the ‘Q’ would become ‘super’ by being a function of the 2 different outcomes. Tentatively this could be done by multiplying the two values (alternative formulations could be defined by societal values or by ethicists, depending on your wont). Costings would be carried out in the usual manner and a super ICER could be calculated. Furthermore, the net benefit approach could be implemented in the usual way; possibly with separate willingness-to-pay values for each input to the super QALY (indeed, they may be willingness to pay values from different agents). The table below summarises how the approach might accommodate the various tensions in health economics.

Equity analysis Health utility analysis
Equity Effectiveness
Life Morbidity
Non-welfarism Welfarism
Fulfilment Satisfaction
Society The individual

All public policies could be subject to an equity analysis in the way set out above. It is in no way health-specific. Each policy field could then us this to weight their usual outcomes measures – preferably utility-based – to estimate the cost-effectiveness of their intervention. At this point the super QALY makes it onto daytime TV and health economists form a new unelected chamber at the Palace of Westminster.

No doubt this explicitly extra-welfarist approach to the super QALY raises more questions than it is currently able to answer, but we need to get on with trying stuff like this. The super QALY has proven elusive to date but, if we do make it, it may solve a lot of our problems. We may find ourselves having to invent new things to argue about.

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A comment on health inequality

A recent article by Benjamin Ho and Sita Nataraj Slavov, which I picked up via Marginal Revolution, argues that health inequality is falling. The argument is that life expectancy for the 1% dying at the bottom end of the age-at-death distribution has increased by more than the life expectancy for the 1% at the top. I’m struggling to think of much academic work being done to look at levels of health inequality in this way. However, I’m not sure what answering such questions could add.

Existing work

Plenty of work has been done on how to measure health inequality. It seems a pretty heinous crime to talk about health equality without mentioning Culyer and Wagstaff. More recently, new models of health inequality have been developed that bare varying levels of equivalence to a standard concentration curve (see herehereherehere etc). But the authors of the aforementioned article are really interested in pure health inequality, irrelevant of income or socio-economic indicators. Some work has been done here too (see here, here, here etc); indeed, the age-at-death distribution thing was done by Le Grand.

Pure health inequality

Health and income are very different in a number of ways, and it seems a misnomer to compare income inequality with health inequality. The most important difference, probably, is how society views the two. Society has some aversion to income inequality and also aversion to health inequality. However, we don’t just prefer a more equal distribution of health; we want equal full health (i.e. health maximisation). Assuming diminishing marginal returns to health care (in terms of health), we will tend to prioritise those in worse health and tend towards equality. I would argue that health can only increase indefinitely in terms of longevity. We may live longer and longer but I think ‘full health’ is a very real ceiling while we’re alive. It simply isn’t possible for a super-rich elite to develop in terms of health. What would these people be like? Bionic presumably, but that’s a different debate. Even if health could be amassed indefinitely it wouldn’t be, as health has no value in exchange.

For me (given society’s aversion to inequality, technological progress and a maximum level of health at any point in time), movement towards equal health seems inevitable. You don’t need to agree with the Grossman model to accept that health represents a kind of ‘stock’. It therefore bares more resemblance to wealth than to income. Health requires some effort to maintain, but not to the same degree as income. Ho and Slavov’s article also introduces the idea of a lottery; luck plays an important role here. Society reacts differently to an income shock (say, unemployment) than it does to a health shock (say, being hit by a car). As with income there might be fair and unfair inequalities, but either way society is going to attach more weight to reimbursing an individual’s loss of health than an individual’s loss of income (unless, maybe, the latter is a result of the former). The same applies to those dealt a nasty hand at birth. In countries where health care is dependent on ability to pay there will certainly be more of a link between health and income; and thus between health inequality and income inequality. In countries like the UK, income inequality seems less likely to affect health inequality.

Health is becoming more equal; I won’t disagree with that. But, for the reasons outlined above, this seems somewhat inevitable. I suppose that doesn’t mean we shouldn’t celebrate it, but it does raise into question the value of doing so when there are real discrepancies between different demographics’ health that need addressing.

Cynics may spot the benefit of such an approach for those at the top of the income distribution…

 

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Some thoughts on evidence-based policy

I’m currently reading Les Mis (I have been for about 2 years – it’s half a million words long). A few months ago, Hugo described economists to me as “geologists of politics” (géologues de la politique). A pretty smart observation for 1862. It reminded me of a slightly more recent quip by Oswald Falk; telling his friend John Maynard Keynes that all he had really done was codify “the moral feeling of an age”.

Economic theory often follows political theory, no doubt, and policy can follow from either. But there are now calls in the UK for ‘evidence’ to enter the equation; most recently in eduction. In regard to economic and public policy, the argument is presumably that the story should go:

political theory > economic theory > evidence > policy.

A loose parallel in medicine might go:

medical theory > treatment > evidence > policy.

In medicine this is usually feasible, as human biology is relatively predictable. It is reasonably clear how medical questions can be answered; usually by randomised controlled trials and epidemiological studies. But is the step from theory to evidence as simple in public policy?

Evidence-based policy

In public policy, the story rarely goes as described above; evidence can fall anywhere in the schema – usually at the end. Evidence is retrospective, while policy is prospective. Human evolution is relatively slow, and what a drug does to a person now it is likely to do in 12 months’ time. Evidence collected in a trial is therefore largely applicable in the future. The same cannot be said for economies and societies. Evidence becomes heavily dependent on projections of what will happen in the future, and we (economists, humans) are notoriously bad at making predictions.

Evidence-based medicine (future edition)

Medicine is less dependent on projections, so evidence-based medicine is usually a safe bet. However, with the rise of personalised medicine, evidence-based medicine as we know it could be off the table. In personalised medicine, n=1. It won’t be possible to stratify trials by the four quadrillion different human genetic combinations; let alone different socio-economic indicators. Furthermore, some pressing questions are proving to be beyond the scope of evidence and prediction. For example, Richard Smith and Joanna Coast recently highlighted the limitations of evidence in antimicrobial resistance.

I’m all in favour of evidence-based medicine, as I’m not a moron! I’m also in favour of evidence-based policy wherever we can do it. But we need to acknowledge its limitations and avoid hubris whenever we do have ‘evidence’. Health economists live in a very evidence-based world, which is no bad thing, but we mustn’t restrict ourselves to it. We need to consider that, if we can’t find evidence of support for a policy (say, attaching a greater weight to end of life care), it may be that our theory is wrong.

When would the NHS have been created, had we waited for the evidence (or economic theory, for that matter)? How long can we wait for evidence in the case of antimicrobial resistance? In the long run we could all, quite literally, be dead. Sometimes it will be necessary to charge forward with policies that we know are right, but just can’t prove. The economists will add the veneer of theory later.

 

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