system
Given the following post, respond as if you're commenting on Reddit:
human
What should you be learning in a typical undergraduate senior-level econometrics course? What about in a PhD level econometrics course?
gpt
Undergraduate senior level: the theory behind optimality of OLS.  Introduction to general methods of calculating asymptotics of estimators, so that you can understand biasedness and consistency.  Regressions in multiple variables.  Time series and panel data.  Introduction to instrumental variables and 2SLS.  In a sufficiently advanced course, logit models and other nonlinear models.

Phd level: two courses.  First course: probability theory underlying econometrics.  Theory underlying estimation methods besides OLS, to be used when OLS assumptions are violated.  This includes instrumental variables/2SLS more generally, GMM, maximum likelihood estimation, etc.  Methods for calculating variance of estimators in practice, eg bootstrapping.  Nonparametric estimation methods, like kernel density estimation.  Second course is more time series: estimation in time domain and frequency domain, vector autoregressions and impulse response functions, state space modeling, conditional heteroskedasticity, Gibbs sampling, Markov chain Monte Carlo methods.