A good number can still leave a bad question
When an economy grows, whose everyday life improved?
An economic statistic is useful. It is also incomplete. Growth, inflation and employment figures tell us something different about the same country, often at the same time.
The difficulty begins when a useful measure becomes a complete explanation. A national average cannot tell us how a renter in one city, a retiree in another or a small business owner somewhere else is managing. Their experiences may be very different without making the aggregate figure false.
This is why charts need definitions, dates and denominators. Is the change nominal or adjusted for prices? Does it describe a total, an average or a median? Over what period? Which population is included?
The purpose is not to distrust every number. It is to know what a number is capable of telling us before asking it to settle a larger argument.
If we can keep the statistic and the person in the same frame, we may begin to understand more than either can tell us alone.