How to teach critiquing data in the media

Statistical literacy means not taking numbers, percentages and graphs at face value. Students learn to ask who was surveyed, how many, who is telling them and why, and whether a graph is drawn fairly. It protects them from being misled by an ad, a headline or a social media post.

Critiquing data in the media is typically taught in Year 5 and Year 6. It builds on earlier work reading graphs and finding averages, and it develops the reasoning behind the Australian curriculum outcome AC9M5ST02, which asks students to interpret and question data claims.

Four questions work for almost any claim: Who was asked? How many people? Who is telling me this, and why? And does the graph start at zero? Asking these turns a vague headline or advert into something a student can judge rather than simply believe.

The most common trick is a bar graph whose scale does not start at zero, which exaggerates small differences so one bar looks far bigger than another. Placing a misleading graph next to an honest one of the same data makes the distortion obvious to students.

Correlation means two things happen together, while causation means one actually causes the other. Ice cream sales and sunburn both rise in summer, but ice cream does not cause sunburn; the hot weather drives both. Assuming that things happening together must be cause and effect is a common error.

Because ads, headlines and posts constantly use numbers and graphs to persuade, and many are misleading. Teaching students to ask who, how many and why, and to check whether a graph is fair, gives them a defence against being manipulated by numbers that look convincing but do not hold up.

A small or biased sample cannot fairly speak for everyone. 'Four out of five people prefer it' means little if only five were asked, or if they were chosen to give the desired answer. Students learn to ask how many were surveyed and who, before trusting the claim.