What Is Deflation? Causes and Effects

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Deflation is a sustained decline in the general price level of goods and services across an economy. When the overall price level falls, each unit of currency buys more than before, so the purchasing power of money rises. In practice, deflation is measured as a negative inflation rate in a broad index such as the Consumer Price Index. A price drop in a single product, or a one-month dip, does not count.

How Deflation Works

Deflation is calculated the same way as inflation, using a price index:

Inflation rate = (Index this period − Index last period) ÷ Index last period × 100

A negative result means deflation.

Hypothetical example: a consumer price index stands at 250.0 one year and 245.0 the next.

(245.0 − 250.0) ÷ 250.0 × 100 = −2.0%

Prices fell 2% on average. A basket of goods that cost $1,000 now costs about $980, and $1,000 in savings buys roughly 2% more than it did a year earlier.

Deflation lowers the nominal prices of capital, labor, goods and services. If all prices fell by the same amount, relative prices would not change: a worker’s wage would buy the same mix of goods as before. Real economies do not adjust evenly, however. Debts, rents and many wage contracts are fixed in nominal terms and fall slowly or not at all. That uneven adjustment is where most of deflation’s effects come from.

Interpreting a deflation reading

A single negative monthly figure can come from a sharp drop in one volatile category, such as energy, while most other prices keep rising. Economists look for declines that are broad across categories and that persist over time before calling it deflation.

What Causes Deflation?

Prices fall across an economy when the supply of goods and services grows faster than the money and spending available to buy them. Several forces can produce that imbalance.

Falling aggregate demand. Demand-driven deflation occurs when households, businesses and governments spend less in total. Common triggers include cuts in government spending, stock market declines that make people feel poorer, higher household saving and tighter monetary policy such as higher interest rates. Firms with unsold inventory cut prices to attract buyers.

A contraction in money and credit. Central banks such as the Federal Reserve have the largest influence on the money supply. If money and credit shrink while output holds steady, prices tend to fall. Bank failures can destroy deposits, which are the bulk of the money people actually spend. An increase in base money therefore does not always prevent deflation: if banks stop lending and people hoard cash, the money that circulates can still fall. Deflationary episodes have often followed long periods of rapid monetary and credit expansion that then reversed.

Productivity gains. Technology can lower production costs, and competition passes those savings on as lower prices. Such declines are usually concentrated in specific industries. For example, the average cost of one gigabyte of data storage fell from about $437,500 in 1980 to around three cents by 2014. If productivity growth is broad enough for output to outpace money and credit, the overall price level can fall.

Imported deflation. A country can also import lower prices, for example when its currency strengthens and makes imports cheaper, or when cheaper goods from abroad compete with domestic products.

Effects of Deflation

On its face, deflation helps consumers: the same nominal income buys more over time. The problems arise for people and institutions with fixed nominal obligations.

Borrowers. Debt does not shrink when prices fall. A borrower repays a loan with money worth more than when it was borrowed, and if wages and business revenues fall with prices, the same payment takes up a larger share of income. This hits households, highly indebted companies and countries with large public debts.

Real interest rates. The real interest rate is roughly the nominal rate minus inflation. In a hypothetical case with a 3% loan rate and −2% inflation, the real rate is about 5%. Because nominal rates cannot be cut much below zero, deflation can leave real borrowing costs high even after a central bank has cut rates as far as it can.

Spending and investment. If buyers expect prices to keep falling, some may delay purchases, and businesses may postpone investment. Weaker demand can then push prices lower still.

Financing choices. Deflation makes debt financing less attractive for governments, companies and consumers, and favors financing from savings and equity. Investors tend to favor companies with large cash reserves and little debt, while heavily indebted firms with little cash look riskier.

Workers. Employers facing falling revenue may need to cut labor costs, but nominal wage cuts are hard to make, so the adjustment can come through layoffs instead.

Historical and Economic Perspectives

The United States last experienced significant deflation in the early 1930s, when bank failures caused a sharp fall in the money supply during the Great Depression. Japan went through a long period of deflation starting in the 1990s, and other economies have recorded deflationary periods in modern times.

Because deflation coincided with mass unemployment and defaults in the 1930s, most economists came to see it as harmful, and central banks shifted toward policies that kept the money supply growing. That stance sometimes produced inflation and encouraged heavy borrowing.

Several economists shaped how deflation is understood:

• Irving Fisher built a theory of depressions around debt deflation. After an economic shock, debtors sell assets to repay loans, credit contracts, prices fall, real debt burdens rise, and more liquidation follows, which can spiral into a depression.
• John Maynard Keynes warned that falling prices during a recession could deepen pessimism, as declining asset values reduced the willingness to invest.
• Milton Friedman argued that optimal policy would aim for deflation equal to the real interest rate on government bonds, so the nominal interest rate would be zero. This became known as the Friedman rule.

More recent research challenges the automatic link between deflation and depression. A 2004 study by Andrew Atkeson and Patrick Kehoe covering 17 countries over 180 years found that 65 of 73 deflation episodes occurred without a depression, and 21 of 29 depressions occurred without deflation. Their findings suggest that the cause of falling prices matters. Productivity-driven declines can coexist with growth and rising living standards. Deflation driven by collapsing demand or a credit contraction tends to raise real debt burdens, delay spending and increase unemployment.

How Governments Fight Deflation

Policymakers usually respond with expansionary measures. Central banks can lower target interest rates, reduce bank reserve requirements and buy government securities to add money and credit to the system. On the fiscal side, governments can increase spending and cut taxes to raise household and business demand. When rates are already near zero, fiscal policy and large-scale asset purchases carry more of the load.

Deflation vs. Related Terms

• Disinflation is a slowdown in the rate of inflation. Prices still rise, just more slowly (for example, from 5% to 2%). Deflation means prices actually fall.
• Relative price declines affect particular goods, such as electronics, while the overall price level rises.
• Stagnation describes weak or no economic growth. It can occur with or without deflation, though falling demand often links the two.
• Deflationary gap refers to output below its potential level, measured against GDP. It creates downward pressure on prices but does not by itself mean prices are falling.
• GDP deflator is a price index used to convert nominal GDP to real GDP. Despite the name, it measures inflation or deflation alike.

The Bottom Line

Deflation matters most to borrowers, heavily indebted companies, governments with large public debts and workers whose employers face falling revenue. Its cause shapes its impact: productivity-driven price declines can coexist with growth, while deflation from collapsing demand or shrinking credit raises real debt burdens and unemployment. Investors in such periods tend to favor companies with large cash reserves and little debt.