20% greater risk of getting bowel cancer if you eat bacon sandwiches!  So said the headlines in October 2007.

Of course we're all used to newspaper headlines which aim to shock us with eye-catching numbers.  But how worried should we actually be by statistics such as this?

Professor David Spiegelhalter, the expert speaker in the videos in this pack of resources, loves analysing headlines to find out what if any truth there is in them!  Using a straightforward numerical approach he shows us how to work out what is really being said so we can decide for ourselves what the risk is in eating bacon sandwiches - and whether we need to stop eating them or not.

Through watching David's video clips and working through some of the resources, students will be sensitised to the need to dig a bit deeper and not simply believe all that they hear.


The resources in this pack complement the video clips, providing activities designed to help students understand how the maths they are taught in school can help them to become better informed about such issues.  Some are designed to be used with the video clips, while others extend and/or provide alternative approaches to students' understanding of risk.  Answers and additional notes are also provided.

The video clips and easier follow-up resources (labelled *) can be used with most secondary students.  Those labelled *** may be more suitable for older students preparing for public exams, such as GCSE or equivalent.

Any of these resources can be used alone - although students may find it easier to understand them if they have seen the preceding video clip(s). 

Type of Resource Resource Name Difficulty Notes
notes icon Teacher notes and worksheet answers   Start here!
video icon Evaluating Risk: Introduction * Introductory video clip (1 min 54 secs)
video icon Bacon Sandwiches * Video clip (4 mins 38 secs)
presentation icon Bacon Sandwiches * Follow-up presentation - this covers the same ground as the video clip, but will help students who need to go through it more slowly, stopping the presentation as necessary.
worksheet icon What does a 20% risk on top of a 5% risk really mean? * Follow-up worksheet - calculate 5%, 20% and then 20% of the 5% using smiley face grids.  Hence discover what 20% of 5% means.
worksheet icon It's a risky business * Follow-up worksheet - absolute and relative risk, working with whole number percentages, and percentages of percentages, displayed on smiley face grids.
video icon Risk Stories ** Video clip (4 mins 33 secs)
worksheet icon Statins ** Follow-up worksheet on the issue discussed in the video clip - working with a number of different ways of representing % risk.
worksheet icon The journey to school * Data on the risk of accidents on the way to school presented in graphical form for students to interpret and evaluate - worksheet.
activity icon The Risk Game *** Harder activity - matching factual statements with figures in headlines, then completing the headlines; requires fairly sophisticated use of percentages.
worksheet icon True or False *** Harder worksheet - using publically available data to decide whether headlines are true or false.
This is intended to provoke class discussion, and to encourage students to use maths to dig beneath headline figures.
worksheet icon Smiley Faces   Sets of 100 smiley faces to use with any of the other worksheets or more generally