Questions tagged [log-linearization]

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Log Linearising CES demand

I have been trying to log-linearise the demand function that follows from a standard two-good CES-utility maximamalisation problem. That is: Maximise \begin{eqnarray} U(h,c)= \left(G_1^{\rho}+ G_2^{\...
0
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1answer
78 views

log linearize exponential expressions

How do I log-linearize an expression like: $e^{(\theta*(x_t-\bar{x}))}$ Where $\theta$ is any constant and $\bar{x}$ is the steady-state of $x$ Generally when we log-linearize say $x_t$, we write it ...
1
vote
1answer
99 views

New Keynesian Phillips Curve: log-linearization

I am facing some problems in log-linearizing the following equation: which is the New Keynesian Phillips Curve (NKPC). The expected result, once log-linearized, is: which is described by equation 46 ...
1
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0answers
54 views

Percent change vs difference in logs: Which to prefer when forcasting non-stationary series with rare large excursions?

One of the most common ways to convert a non-stationary time series into a stationary one is to take the difference in logs. This is approximately equal to the percentage change for small changes, and ...
2
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0answers
119 views

Log-linearization of CES production function

I am trying to recover the Log-linearisation of a CES production function in a paper. Although I am fairly confident with Log-linearisations, I simply do not find the supposed result. The production ...
3
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2answers
337 views

First order condition of log functions in general and interpretation

In the following, a first order condition for a log function is calculated. I know how the left part was calculated, however, I am a little bit confused where the gamma on the right site comes from ...
2
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0answers
41 views

Log deviation from steady state - understanding a journal paper

I hope a question like this is fair game on this website! I'm doing some research for my thesis, and have come across what seems to be a pretty simple model - two countries, A (representing the USA) ...
2
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0answers
34 views

Linearization around the steady state (Asset pricing application)

I am working through a linearization example from Colacito and Croce (2011). In the paper the following expression is derived: \begin{align} & (v^{i}_{c,t})^{\theta}=E_{t}[\delta e^{\Delta c^{i}_{...
2
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0answers
83 views

Log- Linearization of equations

can somebody help me understand how it is possible to log-linearize this equation? $$\frac{1}{1+i_{t}}=\beta E^i_{t}\left[\frac{P_{t}}{P_{t+1}} \cdot \frac{U_{c}\left(C_{t+1}^{i}, \xi_{t+1}\right)}{U_{...
2
votes
1answer
264 views

Log linearising EUler equation

I am trying to solve a problem that asks to log linearise following Euler equation of the New Keynesian model: $$C^{-\sigma}_t=\beta E_tC^{-\sigma}_{t+1}(1+i_t)/(1+\pi_{t+1}).$$ The solution is ...
1
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0answers
16 views

Are typical macro DSGE (RBC or New Keynesian DSGE) models linear, non-linear, or log (linearized)?

In Carl Hommes 2015 book on Expectations, it seems he considers DSGE models (being it either RBC DSGE or New Keynesian DSGE) to be linear, or (log)linearized models, on page 3 of the introduction. He ...
3
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0answers
165 views

Log-linearizing a non-separable utility function around the steady state

I've started reading Jordi Galí's Monetary Policy, Inflation and the Business Cycle (2nd ed., 2015). In section 2.5.2, Galí considers an example with the following non-separable period utility ...
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1answer
699 views

Constant elasticity proof for log-linear demand curve

From Perloff 2008e solved 2.2: Q: Show that the elasticity of demand is a constant e if the demand function is log-linear, ln Q=ln A+e ln p. A: Differentiating with respect to p, we find that (dQ/dp)/...
1
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1answer
246 views

How do you use a Log-linear model when you have negative Xs?

I am trying to us a Log-linear model to derive an elasticity. However, some of my Xs are negative numbers. Being as the model relies on the natural log of the Ys and the Xs, how can this model work ...
1
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0answers
47 views

log linearization around steady state (price dynamics)

I'm stuck with a derivation from Gali's book. In the version 2008, I can't get eq. (7) from chapter 3. All is ok until the following: $$ (1-\epsilon)\log\pi_{t}=\log(\theta+(1-\theta)\exp[(1-\...