Evidence based medicine and evidence based policy

There was a fair bit of media coverage of the finding that teenage-pregnancy-prevention programmes using simulated babies are associated with an increased rather than decreased teenage pregnancy rate. Some of the media discussion focused on the role of evidence in public policy.

Via Twitter, I came across this article on evidence-based policy by Howard White in The Independent

Evidence-based medicine has transformed medical practice. TheCochrane Library has published more than 6,000 studies summarising high quality evidence for health interventions. Notable cases include breast screening, which used to be recommended for women from the age of 40 until the evidence showed that the number of false positives recorded was in fact doing more harm than good. The risks from unnecessary surgery were greater than the often small benefits from early treatment forbreast cancer.

Hormone replacement therapy (HRT) is another example. It was routinely used to reduce heart disease, but then became far less common when evidence showed adverse effects. There is now a more nuanced understanding of which women will benefit from HRT and which will not.

Prior to Cochrane, doctors based their advice on out-of-date knowledge, personal experience and the influence of drug reps. Today, doctors have access to evidence-based guidelines. Decisions on what the NHS can and should fund are informed by the advice of the National Institute for Health Clinical Excellence after a review of the evidence.

So why can’t we do the same for social and economic policy?

For those who are interested, I engaged (or am engaging) in a twitter exchange on this with Howard White, whose replies have been very gracious. As in so many of these exchanges I suspect that we agree on more than we disagree on (and possibly agree on everything with a difference in emphasis)

Of course policy should be based on evidence, where available. This not only seems extremely reasonable and  rational – it is eminently reasonable and rational. I also write as an admirer of the Cochrane Collaboration.

However, I always feel a sense of caution when clinical concepts are introduced into political discourse. The best definitions of EBM always include the word “judicious”, as here

“Evidence-based medicine is the conscientious explicit and judicious use of current best evidence in making decisions about the care of individual patients.”

Judicious is key – judgment and reflection are required. Does this body of evidence apply to my patient, this individual person in front of me, or does it not? As I wrote on another point:

it is one thing to have an evidence base for a specific therapy in medical practice, quite another for a specific intervention in society itself.

My review of Helen Pearson’s The Life Project is still to be published, when it does I will perhaps write a little more on “evidence-based policy”, a concept which began to enjoy great vogue in the 1990s.What Pearson’s book shows, however, is that the devil can cite evidence for his own purpose; “evidence” can be wielded with agendas.

Obviously the Campbell Collaboration aims to address this, by being transparent about the evidence used and the methodology used to synthesise it.

A further point is that evidence-based policy tends to presuppose consensus on the ends of policy  – and emphasise technocratic means of getting there. Thereby the focus on specific interventions, rather than any wider sense of not merely social goals but of social meaning. Of course, this very much in keeping with a time in which we are all supposed to be beyond “grand narratives” – which is of course itself a “grand narrative.” I would suggest that many recent events in politics around the world are best understood as testing this notion to destruction.

Bringing it all back to a question I asked a while ago about the best kind of evidence for health informatics innovations, perhaps what this illustrates is that the way we do evidence now tends to be to focus on specific interventions and, as far as possible, measure their effects as specific interventions and without reference to an overall system. Indeed, this is obviously necessary for assessing therapies and treatments. But is it necessarily missing something when it comes to a system?

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