We’ve started to get a sense of some of the different ways that the media uses data to make you think numbers are big or small, but sometimes, to understand the size of a number, we need to compare it to something else.

In this video, Mark introduces some useful comparisons for particular kinds of data - such as comparing to other countries and looking back through time.

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.

It may sound like a silly question, but if we want to make sense of data in the media, then whenever we hear numbers quoted, one of the first things we should be asking is - is that a big number? If someone’s spending money on you, they’re likely to want to make that figure sound as impressive as possible; on the other hand, if someone wants you to spend your money on them, they’ll want to make that figure sound as small as possible.

In this video, Mark explains some of the ways that big numbers can be made to sound small and small numbers can be made to sound big.

Does 0.1% sound like a big number? Stripped of important context, it’s almost impossible to tell.

Context is crucial in understanding whether numbers are big or not, particularly when it comes to percentages. 2% might sound like a small number of people, but if it’s of all people in the world, it’s a lot; 80% might sound like a lot of people, but if it’s of the people who work in your office; it’s a lot less. Whenever we see percentages quoted, we should be asking “as a percentage of what?”, “how much does 100% actually correspond to?” and “what is 100%; a number of people, a sum of money, or something else?”.

In this video, Mark demonstrates how numbers can look big or small in relation to the whole ecosystem in which they sit.

Learn how to make sense of social statistics and economic data with this introductory course on quantitative social science.

https://www.futurelearn.com/courses/media-data

Increasingly, we’re bombarded with all sorts of data about how society is changing: opinion poll trends, migration data, economic results, government debt levels and MPs’ expenses claims. The ability to read such information with confidence is an increasingly important skill for both modern citizens and those studying the social sciences.

In this free online course, we’ll look at ways of cutting through the confusion to decide what numbers reveal, and when and why they (sometimes deliberately) mislead.