Paradox of thrift

The paradox of thrift (or paradox of saving) is a paradox of economics. The paradox states that an increase in autonomous saving leads to a decrease in aggregate demand and thus a decrease in gross output which will in turn lower total saving. The paradox is, narrowly speaking, that total saving may fall because of individuals' attempts to increase their saving, and, broadly speaking, that increase in saving may be harmful to an economy. Both the narrow and broad claims are paradoxical within the assumption underlying the fallacy of composition, namely that what is true of the parts must be true of the whole. The narrow claim transparently contradicts this assumption, and the broad one does so by implication, because while individual thrift is generally averred to be good for the economy, the paradox of thrift holds that collective thrift may be bad for the economy.

It had been stated as early as 1714 in The Fable of the Bees, and similar sentiments date to antiquity. It was popularized by John Maynard Keynes and is a central component of Keynesian economics. It has formed part of mainstream economics since the late 1940s.

The argument begins from the observation that in equilibrium, total income must equal total output. Assuming that income has a direct effect on saving, an increase in the autonomous component of saving, other things being equal, will move the equilibrium point at which income equals output to a lower value, thereby inducing a decline in saving that may more than offset the original increase.

In this form it represents a prisoner's dilemma as saving is beneficial to each individual but deleterious to the general population. This is a "paradox" because it runs contrary to intuition. Someone unaware of the paradox of thrift would fall into a fallacy of composition and assume that what seems to be good for an individual within the economy will be good for the entire population. However, exercising thrift may be good for an individual by enabling that individual to save for a "rainy day", and yet not be good for the economy as a whole.

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