Matrix Evidence

For anyone interested in evaluation of social policy, the US Government Accountability Office (GAO) is an extremely useful source of robust evidence.

The GAO was recently asked to take a look at an initiative delivered by the Coalition for Evidence-Based Policy. The Top Tier evidence initiative involved the CEP reviewing the evidence associated with 63 different interventions; of those 63, the CEP rated 6 as top tier, defined in Congressional legislation as ‘well-designed randomized controlled trials [showing] sizeable, sustained effects on important ….outcomes’.

The GAO concluded that RCTs are the best way of providing robust evidence of intervention effectiveness. However, they also noted that RCTs are often difficult to conduct in the context of social policy evaluation. For that reason, reliance on only evidence from RCTs would severely limit the evidence available to policy makers. Therefore the GAO concluded that several rigorous alternatives should be considered including quasi-experimental designs and statistical analysis of observational data.

Other important points raised by the GAO included: (i) the decision to adopt an intervention will be informed not just by evidence of effectiveness, but also by data on costs and benefits, and suitability to local communities, and (ii) improved evaluation would help identify effective interventions.

Tags: Add new tag, evidence debate defence, randomised controlled trials
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The sales of antidepressant drugs are rising in most Western countries. The proportion of Americans taking antidepressants in any given year nearly doubled from 1996 to 2005. The figures on volume of sales are similar in the UK. Received wisdom has been that the figures reflect a rise in the number of people diagnosed with depressive illness.

However, a recent paper published in the British Medical Journal suggests that not to be the case. The authors examined medical records from 1.7 million British patients that had visited their family doctors. They found that antidepressant sales rose strongly between 1993 and 2005. However, the rise was not because more people are taking these drugs, but because of an increase in the duration of treatment amongst the antidepressant users. It’s not that more people are taking them, it’s that people are taking them for longer.

The research showed that the rate of diagnosed depression remained steady from 1993 to about 2001, but then fell by about a third in the period to 2005.

Tags: Add new tag, evidence-based policy, medicine
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Health reform is one of the hottest policy debates currently raging in the US. In a recent contribution, Lara Shore-Sheppard argues that which ever side of the debate you favour, one thing is clear: “doing nothing is definitely worse than doing something”.

In a paper published by the National Bureau of Economic Research, Shore-Sheppard looks at the effects of recent Medicaid expansion on a range of factors including the private health insurance market and children’s visits to the doctors.

The paper concludes that so-called ‘crowd out’ effects on the private market are small, and that whilst children with Medicaid cover are more likely to seek medical attention, expanding coverage is no silver bullet.

Shore-Sheppard is clear that research must feed into the policy development process. “It’s not always a seamless transition from research to policy” she says, “but good policy will be based on the evidence that exists.”

Tags: Add new tag, evidence-based policy, medicine
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