Now introduce price stickiness into this model, as in Linnemann and Schabert [2003].
To ensure uniqueness, assume the short interest rate is determined by a Taylor rule
with a coefficient on expected inflation greater than 1. Following a shock to government
spending, GDP increases because of the increase in aggregate demand while some firms
cannot change their price. Like in the neoclassical model, consumption falls because of
the negative wealth effect on forward-looking agents.
To obtain an increase in private consumption, other frictions are needed. Galí, López-
Salido and Vallés [2003] assume that a fraction of agents (the “Rule of Thumb” , or
“ROT”, consumers) cannot save or borrow: hence, they consume their wage period by
period. Following a government spending shock, aggregate demand increases because of
the presence of sticky prices; labor demand increases, and if the labor supply of ROT consumers is not too elastic, the real wage increases instead of decreasing as in the neoclassical
model. With enough ROT consumers, private consumption and GDP also increase. Private
investment does fall, but only slightly for reasonable values of the capital adjustment
costs.