Another way that the media uses data is to report change and risk - how much has something increased or decreased? If you start a particular behaviour, how much does that increase your risk of a particular outcome? As we saw earlier, when numbers are stripped of context, it can be difficult to tell whether they are as dramatic as they seem. This is even more strongly the case when we look at differences between percentages or differences without a common baseline, as in the case of risk.

In this video, Mark explains the difference between percentage increases and percentage point increases and between absolute and relative risk. Don’t worry if you don’t quite catch these concepts first time round, we’ll revisit them in the next step to make sure you’re following.