Testing government policies first means we spend public money better – so why are we so bad at doing it?

'Scared Straight' schemes, which expose young people at risk of turning to crime to prison life, actually made them more likely to become criminals. Many factors influence policy decisions, but prejudice and ignorance should not be among them

Evidence could help teachers and policy makers to understand how the Pupil Premium could best be spent (Getty)

In the US, just one dollar of Government spending out of every 100 is backed by evidence. That figure is unlikely to be any better in the UK.

The Government is supporting education for the disadvantaged through the Pupil Premium – but spending cuts have also led to the closure of many Sure Start centres intended to help those same children in the crucial early years. Government policy promotes exercise to tackle growing obesity, but then cuts threaten the closure of sports centres and swimming pools. Where is the evidence for these spending decisions?

Evidence-based medicine has transformed medical practice. The Cochrane 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 for breast 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Prior to Cochrane, doctors based their advice on out-of-date knowledge, personal experience and the influence of drug reps.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?

We can and we are – but to far lesser extent than we should. The effectiveness of social and economic policies and programmes can be tested in the same way the effectiveness of drugs, and that is being done more and more. But the UK lags behind Nordic countries which have set up specialised research agencies to provide evidence to inform government policy in health, education and other social spending, such as housing.

We know that testing policy works. A Campbell review showed clearly that “Scared Straight” schemes, which expose young people at risk of turning to crime to prison life to discourage them, actually made them more likely to become criminals. The US Department of Justice now advises states not to adopt that approach. A newer review shows that the curfews on young people, common across the US, are not effective in reducing crime. Hopefully the Department of Justice will pay heed.

In the UK, the Education Endowment Foundation, supported by government and the Big Lottery, has involved more than a quarter of primary schools in studies of how to improve educational performance. The evidence is being used by a growing number of schools in deciding how to spend the Pupil Premium. And policy experts will meet in London in September to share experiences from around the world about evidence-based policy and what works.

But there are many clear findings which are simply not being used. Of course, many factors influence policy decisions – but prejudice and ignorance should not be among them. Policy makers, professionals such as teachers, and also the public need greater awareness of what evidence there is about how we should spend public money, and which of that evidence is good evidence.

When confronted with a new policy or proposed practice, we should always ask: where is the evidence?

Howard White is chief executive of Campbell Collaboration