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Paradox of Thrift
Suppose people decide to become more thrifty, that is,
they decide to save more at each level of income. One might
expect that this would increase the total amount of savings,
but the simple Keynesian multiplier model predicts a
paradox of thrift, that total savings will remain the
same and income will decline.
If people become more thrifty, they consume less at each
level of expected income. On a graph increased thriftiness
can be illustrated as a shift downward of the consumption
function or a shift upward of the savings function. If you
draw in these shifted lines, you will see that equilibrium
income will fall. But since in equilibrium savings plus
taxes must equal investment plus government spending, and
because by assumption investment, taxes, and government
spending are fixed, in equilibrium savings cannot change. In
fact, if we allowed investment to increase a bit with income
(but not by too much, or the model has an unstable
equilibrium), then the investment line would slope upwards a
bit. At the new equilibrium caused by increased thriftiness,
savings would actually be less.
Another way to illustrate the logic of the paradox of
thrift uses the analogy of the leaky
bucket. Consider what will happen if the savings hole in
the bucket is made a little larger, which corresponds to
people becoming more thrifty. Initially there will be a
larger flow of water out. But this cannot continue
indefinitely. Equilibrium exists when the inflow equals the
outflow, and the inflow has not changed. This means that the
water level must drop so that the pressure forcing water out
the bottom will be reduced. Less pressure means less
outflow, and at some lower level of water equilibrium will
be reestablished.
With the paradox of thrift the multiplier model makes an
important prediction of an unintended consequence. Prior to
Keynes, most economists had argued that savings were helpful
to the economy because saving spurred investment, and larger
amounts of capital increased the productive capacity of the
economy. Hence, a slower rate of savings would reduce the
growth rate of the economy. In contrast, the paradox of
thrift implied that more savings could harm the economy.
Many early followers of Keynes, and probably Keynes himself,
were "secular stagnationists" who believed that a
lack of spending was likely to be a chronic problem in an
industrialized economy, and therefore they thought that
measures should be taken to reduce savings. Since the rich
did most of the saving, an obvious solution was to tax the
rich to reduce their incomes and thus their savings. Those
who had wanted to tax the rich with the goal of equalizing
incomes had, prior to Keynes, been confronted with the
argument that such a move would have harmful effects on
growth. It is not surprising that they were often eager to
embrace a theory that implied that equalizing incomes had
only good side effects. (The tendency for macroeconomic
theories to be popular or unpopular as much for their
political implications as for empirical support has existed
for all theories, not just this multiplier model.)
Another implication of the model was that the government
should be more active in the
economy.
 
Copyright
Robert Schenk
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