Economics●●●●●Difficulty 1 of 5

How can a pay rise leave you poorer?

A 2% raise during 4% inflation feels fair. A 2% pay cut with stable prices feels outrageous. They're almost the same thing.

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A pay rise leaves you poorer whenever prices climb faster than your wages. What your money is really worth isn't the number on the payslip but what it can buy, and economists call that its purchasing power. If your income stays put while prices rise, your purchasing power falls. A raise only makes you richer if it outruns prices.

Economists keep two books for this. Nominal value is plain money: 2,000 a month. Real value measures that money against the goods and services it can actually be swapped for, with inflation taken into account. The real number is the one your shopping basket feels.

What one dollar buys as prices rise

base-year dollars

Bar chart: What one dollar buys as prices rise. (base-year dollars)
Purchasing power of $1
Index 1001 base-year dollars
Index 1250.8 base-year dollars
Index 2000.5 base-year dollars
Index 4000.25 base-year dollars
Worked example computed from the rule 100 / price index: each time prices double, a dollar buys half as much.

Our brains mostly read the nominal number, and that has a name: money illusion, a term coined by the economist Irving Fisher, who wrote a whole book about it in 1928. Experiments show how strong it is. People judge a 2 percent pay cut with stable prices as unfair, yet call a 2 percent raise during 4 percent inflation fair, even though the two are almost equivalent.

The same idea works across borders. To compare a dollar with a Hong Kong dollar, economists price the same basket of goods in both places. That comparison, called purchasing power parity, is the serious version of a famous playful measure: the Big Mac Index, launched by The Economist in 1986.

Black-and-white glass-plate photograph of the economist Irving Fisher, a bearded man in a suit.
Irving Fisher, the economist who named money illusion: our habit of reading money's face value instead of what it can buy.Photo: Bain News Service, publisher · Public domain

Quiz me

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  1. 1.Your salary rises 3% in a year when prices rise 5%. What happens to your purchasing power?
  2. 2.A price index stands at 200, against 100 in its base year. What is one dollar worth in base-year dollars?
  3. 3.What does 'money illusion' describe?

Recap

Your money's worth is 100 divided by the price index: when prices rise, each coin buys less.

Surprising fact · Our brains read nominal money so strongly that a raise below inflation feels fairer than an equivalent pay cut, a bias Irving Fisher called money illusion.

Sources (4)

No source, no claim. Every fact in this lesson (15 claims) cites at least one of these.

  1. [1]Purchasing power · Wikipedia
  2. [2]Money illusion · Wikipedia
  3. [3]Real versus nominal value (economics) · Wikipedia
  4. [4]Purchasing power parity · Wikipedia
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