Real vs Nominal

Most numbers you meet are nominal. Dividing by a price index turns them into real ones, and that single division is the difference between a fact and an artefact.

The division that does the work

Nominal means measured in the money of the day. Real means measured after stripping out the change in prices. The operation that converts one into the other is a division: divide the nominal figure by a price index and what is left is the change in quantity.

That is why the phrase real vs nominal is not pedantry. A wage, a revenue line, a growth rate and a bond yield all mean different things depending on which one you are reading.

Arithmetic you can check

Take spending up 5% while prices are up 5%. Divide, and real spending is unchanged, so nothing was produced or consumed more. Now take spending up 4% with prices up 6%: nominal spending still grew, but real spending fell, because more money chased fewer things.

Where the confusion bites

Two traps. The first is the base effect: a rate can fall simply because the comparison period was extreme, not because the present is cooling. The second is mixing a real gain with a nominal cost - a wage rise of 3% against prices up 4% is a pay cut, though the headline number looks positive.

One checkable use: whenever a figure is quoted as growth or as a return, ask which price index was used to deflate it and over what period. An undeflated figure is a nominal claim wearing a real-sounding label.

Related: GDP · Stock vs Flow · Output Gap

Next: Stock vs Flow