Data Made Simple

Points clés

• Three questions settle most numbers your family meets: where did this come from, compared with what, and what is missing from it?
• A percentile on a school report shows the share of children who scored lower, not the percentage of answers your child got right.
• When a headline says something doubles or triples, ask 'from what to what?', because doubling a rare event can still leave it rare.
• Free apps are usually paid for with information, so test each permission against the app's job and choose the middle options where offered.
• A weekly 'number of the week' at dinner teaches children to question figures calmly, especially when you say 'I'm not sure, let's check'.

À l'intérieur de ce bit

1. Data is just careful memory

   If numbers make you tired, start here: data is simply memory written down carefully. The school app, the electricity bill, the step counter and the evening news all hand you data, and it is easy to feel you must understand every figure.

2. Myth: numbers speak for themselves

   Numbers never speak alone; someone chose what to count, how to count it and whom to compare. A sample works like tasting a spoonful of dal.

3. Myth: there is an average child

   School reports lean on averages and percentiles, both easy to misread. An average is the balance point of a see-saw: one very heavy value at the end tips it a long way.

4. Myth: 'twice as likely' means danger

   Imagine a headline announcing that a new kind of phone charger doubles the risk of overheating. Doubles from what?

5. Myth: free apps cost nothing

   Most free apps are paid for with information about the people who use them: what they tap, where they go, whom they know. That is not automatically sinister; a map app genuinely needs your location to give directions.

6. The twenty per cent that does the work

   If you remember nothing else, keep this small kit. Pass every number that matters through the three questions.