A Quick Thought On: Evidence Based Public Policy

I’ve seen the term “evidence based policy(-making)” used quite a bit frequently, and it seems to have come up at this weekend’s Liberal Party of Canada convention as well.  I think that most people, generally, would agree that it’s a good idea to consider evidence when making public policy decisions.  This leads to many disagreements over what exactly counts as evidence, which evidence is more reliable, etc., but I do think at least in theory most people are in support of this idea.  But I do think that there is an important distinction to be made here – evidence should inform our policy decisions but it should not make our policy decisions.  The reason for this is simple – the process of governing is not scientific, and there isn’t a “correct” answer to many potential issues that the government addresses.  There are other concerns that I think are perfectly legitimate to use as decision-making criteria in a democracy, such as what the role of the government ought to be in the first place or whether a given outcome actually ought to be our goal.

For example, I think the argument that “we should bring back capital punishment because it will lower crime rates” is one that the evidence doesn’t bear out.  So if your stated goal is reducing crime, then capital punishment is not a position that the evidence says you should support, and evidence-based decision making should win out.  If, however, you make the argument that “it is irrelevant whether or not capital punishment is an effective deterrent because certain classes of criminals ought to be executed in accordance with the principles of justice” then the evidence doesn’t matter.  The person in the second instance isn’t “anti-evidence” as people will often assert; rather the evidence related to deterrence isn’t a determining factor because deterrence was never their goal to begin with.

I think this distinction is important to make, because people on all sides of the political spectrum are accused of ignoring evidence when it suits their ideology.  This may be true in some instances, but I think it is much more likely to be the case that these are actually arguments at cross-purposes – the people arguing that their “evidence” should be the deciding factor are often arguing from a completely different premise than the people who they disagree with.  I think it’s fair to criticise people when their stated premise is contradicted by sound evidence.  I don’t, on the other hand, think it’s fair to criticise people as hypocritical because there are instances in which they believe other factors are more significant than the evidence.  Public policy is not a science, and it can not be reduced to a series of statistics; the kind of society we’re trying to build is an equally important a factor.  Someone is not a hypocrite because their goals differ from yours.