Numbers in Context
An Index Starting at 100 Shows Change From a Chosen Base
Read an index set to 100 without treating its points as currency, and calculate percentage changes from the right starting value.
CONTEXT FOR EVERYDAY CURIOSITY
Numbers in Context
Use a simple worked example to distinguish percentage-point changes from relative percentage changes, then check the denominator behind a headline.
Numbers in Context
A Population Total and an Annual Migration Flow Count Different Things
Distinguish a population measured at a particular date from migration counted over a period before comparing headline numbers.
Numbers in Context
A Percentage Needs Its Denominator Before It Becomes a Headline
Check what a percentage is a percentage of before comparing headlines, survey results or changes across groups of different sizes.
Numbers in Context
Five Percentage Points Is Not the Same as Five Percent
Use a simple worked example to distinguish percentage-point changes from relative percentage changes, then check the denominator behind a headline.