How to log linearize an equation that has a conditional expectation? Any reference or example would be appreciated.
1 Answer
You need to remember two properties of derivatives and expectations. Everything else stays the same.
$E(f(x))$ is not equal to $f(E(x))$ unless f is linear.
$\partial E(f(x)) / \partial x$ is equal to $E(\partial f(x) / \partial x)$.
Also remember that as a result, linearizing models with uncertainty reduces them to their certainty equivalent version. This may or may not matter for what you are doing.
-
1$\begingroup$ The second bullet point is true only when you impose some regularity conditions on $f(x)$. That being said, you'll almost always get away with assuming said conditions are satisfied when doing economics. $\endgroup$ Jan 12, 2017 at 23:25
-
$\begingroup$ Theoretical Economist - Thank you for your answer. Do you know of any book or journal paper that has some work on the above? $\endgroup$ Jan 13, 2017 at 12:05