7. RBC Flashcards
What are vector autoregressions?
Ways of summarising the dynamics of macro data where we are interested in obtaining the impulse response functions
What are impulse responses?
They trace out the response of current and future values of each variable to a one unit increase (or a one standard deviation increase, when scale matters) in the current value of one of the VAR errors
What does DSGE stand for?
Dynamic Stochastic General Equilibrium model
What is the simplest DSGE?
RBC
What is the New Keynesian model?
It combines DSGE structure of RBC models with assumptions that depart from classical monetary models. Features include monopolistic competition and nominal rigidities
What is the consequence of nominal rigidities on changes in short term interest rates?
They aren’t matched by one to one changes in expected inflation
How do financial frictions impact shocks?
They amplify them
What are business cycles?
Expansions and contractions that appear at the same time in different economic sectors.
They are periodical but with variable duration.
What should business cycle models be able to answer?
The source of cyclical fluctuations and the shock transmission mechanism
What second moments are we interested in?
Variance - volatility
Covariance, cross correlation - co-movements
Autocorrelation - degree of persistence
What are the two extreme cases of persistence?
-A random walk Px=1, the series never returns to average, a transitory shock produced permanent effects
-White noise Px=0, a transitory shock doesn’t generate any persistence, it isn’t possible to identify cyclical fluctuations due to the shock
How persistent are most macro variables?
Highly persistent
What must be added to the Ramsey model to understand aggregate fluctuations?
-There must be a source of disturbances.
-They are added in the form of fluctuation shocks- technology shocks. -This is known as an RBC model
What is good about the RBC?
It provides a coherent framework that integrates growth and business cycles
Why is the RBC controversial?
Because the only fluctuations are technology shocks?
What is the HP filter?
It is a model free approach to decomposing a time series into its trend and cyclical components
How is the parameter lambda used in the HP filter?
If lambda is zero we only care about fitting and if lambda is infinity the trend value will never change from one period to the next
How do we adjust lambda when the frequency of our data increases?
We increase lambda
How do empirical VARs suggest that price level and output react to an increase in interest rate?
The aggregate price level doesn’t respond much initially (inflection inertia) but then goes down. Output falls initially with a j shaped response and zero LR effect
What are the advantages of micro founded models?
-they are elegant
-they can be used to evaluate welfare effects of alternative policy
-we can do counterfactual experiments with them since their deep parameters are generally robust to Lucas’ critique
Conceptually what does the RBC highlight?
The efficiency of business cycles
The importance of technology shocks as a source of economic fluctuations
The limited role of monetary factors
Roles of money in the economy
- Medium of exchange
- Store of value
- Unit of account
What do we call the RBC model with money introduced?
The MIU model (money in utility)
What is the result of the MIU model?
It is able to generate non trivial effects to monetary shocks