Testing environmental policies with randomised control trials

How do we know that what we do to manage biodiversity is doing what we want?

The sad truth is that a lot of the time we don’t. A lot conservation management is done in particular ways because of a mate once told the ranger a certain method was good or because they wish to maintain the status quo, but very little is actually based on evidence.

The best way we have of understanding the effects of management on biodiversity is through properly controlled studies. Despite the increasing complexity in ecology, which is increasingly resembling a branch of applied mathematics, many conservation questions are about whether treatments a or b are better than doing nothing at all.

This is one of the few ways we can attribute causation in ecology and is held as the gold standard for other disciplines. It bears repeating that correlation does not equal causation and most ecology is observational in nature, rather than manipulative.

Although there is a push by some  to answer these questions and compile evidence for particular management techniques (notably the excellent conservationevidence.com), much remains unevaluated. There is a feeling by some publishers that such experiments are boring and this stops researchers pursuing this type of research as well as reducing replication even when they are published.

Though we sometimes have little idea about how to manage biodiversity at the site scale, environment policy can be equally difficulat to implement  Randomised controlled trials (RCTs) have the potential to be powerful tools to aid this decision making. Many policy questions relate to how people interact with their environment. For example, is it best to pay up-front for agri-environment schemes or to pay based on the results they deliver?

Would it be better to pay farmers up front for planting wildflower margins or should we pay them based on delivery?

Questions like this could feasibly be addressed by a large RCT. However, these would need government backing and funding. Some people might see the use of RCTs, when government is cutting such large parts of it’s budget, as an unnecessary indulgence. However, without these trials we are fumbling around in the dark trying to find a sticking plaster when we might be in need of a visit to the hospital. It’s a clumsy analogy but without RCTs of such policy options we do not know whether what we are doing is the best thing to do, or even if it is working at all.

This type of thing is being championed by Ben Goldacre and Tim Harford, who argue we should have RCTs for almost everything. Goldacre has also written a report for Cabinet Office in the UK, so it looks like this idea is gaining a bit of traction. RCTs have been identified as having potential for social policies such as the use of different teaching techniques in aiding reading. However, there is no reason why similar trials couldn’t be designed to test environmental policy.

This big idea would put an end to uninformed policy making on the environment. It would mean that we wouldn’t have to guess at which policy delivers the best results. Politicians would still get it wrong some of the time but at least they’d be presented with good evidence to help them make these decisions.

Politics would still however come first. Making decisions is a messy process and science doesn’t have the last say on such issues. As seen with the recent badger cull debate even the best evidence can have little value when faced with the might of industry lobbyists. But without this evidence, policy making will continue to fumble around in the dark.

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