When policy-makers claim that they want to tackle corruption, they are making a statement about how much of it they think exists. For many, the answer to that question is likely to be simple: “too much”. As a result, politicians are often happy to concentrate on tackling the problems that they see before them, without worrying unduly about broader issues of quantification. There is still, however, the nagging problem of how one empirically illustrates that an anti-corruption policy or approach is working. Before long, that inevitably brings you back to the thorny problem of measurement in some form.

Trying to discern how much corruption exists is nevertheless a task fraught with difficulty. For some (see below), the task is bordering on pointless. You cannot know for sure, so why bother spending lots of time and effort trying to find out? This has not stopped a growing number of organizations and individuals from trying to do justice to the measurement challenge. Some of their approaches are based on perceptions of corruption, some on individual experiences. Others use a range of proxies to measure what they argue might well be corruption. This means that, despite the deep-seated problems inherent in trying to quantify the phenomenon, we now have a range of tools at our disposal. This chapter outlines some of the most well known of these tools, illustrating both what they do well and where they fall down before moving on to analyse how their findings can inform the real world of anti-corruption policy.

As we saw in the previous chapter, there is still no agreement on what corruption precisely entails. Given that, what hope is there of reaching an agreement on how much of it exists? This leads critics to argue that, while most attempts to quantify corruption are no doubt well intentioned, corruption remains a classic contested concept that is, in effect, immeasurable. Corruption, in other words, is like the notions of fairness, freedom, democracy and justice: we know what they are when we see them, but knowing how much we have at any one time is, in any practical sense, impossible.