# Tag Info

Accepted

### Outputting Regressions as Table in Python (similar to outreg in stata)?

You can use code like the following (making use of the as_latex function) to output a regression result to a tex file but it doesn't stack them neatly in tabular form the way that outreg2 does: ...
• 15.8k
Accepted

### What happens if the "control variables" are also endogenous?

"But if any of these control variables are endogenous to some omitted variable, doesn't this contaminate the unbiasedness of ALL the independent variables?" I don't want to emphasize this too much, ...
• 9,127

### Proof coefficient in log-log model is equal to coefficient of elasticity

Because $\Bbb E[\varepsilon \mid x]= 0$ is one of the key assumptions for the estimation.
• 1,262
Accepted

### More complex than simple and multiple regressions?

Welcome to the wonderful world of econometrics! Most introductory econometrics courses will extend Ordinary Least Squares (OLS) by considering binary outcomes models such as the logit and probit. ...
• 116
Accepted

• 2,024

### What should we do if the subsample have the opposite results to the general results?

tldr: As the other two answers also indicated, there is not necessarily a problem with your results. It might be the case that the two subgroups have different distributions of the covariates. ...
• 8,632

### What happens if the "control variables" are also endogenous?

This is an example of what statistician Andrew Gelman calls "the fallacy of controlling for an intermediate outcome". Here is his description of this fallacy popping up when researchers ask if having ...
• 15.8k

### What happens if the "control variables" are also endogenous?

In the context of Least-squares estimation, the way we have to (attempt to) deal with possible endogeneity of regressors is through Instrumental Variables estimation. This approach does not depend on ...
• 31.9k

### rotating and exchanging x for y's in regression

This is a somewhat "dated" subject in introductory econometrics, I suspect because, in econometrics the models come from theories and arguments that try to a priori establish causality and not just ...
• 31.9k

### Robust Standard Errors in Fixed Effects Model (using Stata)

Use -areg- in Stata, and the standard errors will come out as in the textbook. Specifically, the command ...

### How do I calculate price elasticity of demand using historical price and quantity data?

You've fallen into a really common pitfall -- the spurious regression. The parameters you chose to include can't be chosen 'willy nilly' by throwing data into a regress command. Ultimately this can't ...
• 244

### Outputting Regressions as Table in Python (similar to outreg in stata)?

There is now a Python version of the well known stargazer R package, which does exactly this. See also this related question: https://stackoverflow.com/q/35051673/2858145

### Regression on a constant

So basically the question is: If I know the average ($\hat{\mu}$) of the daily temperatures ($y_i$) of last year, does that tell me anything about how many people were born ($x_i$) each day? ...
• 26.2k

### Regression over the whole population

It's important to consider what exactly the population is about which an inference is being drawn. It's easy to overlook the time aspect in this context. Suppose for example that the aim is to ...
• 6,813
Accepted

### Does the linear probability model require the regressand to be zero/one-valued?

The "LPM" label refers to the structure of the equation, not to the estimator. LPM models can be estimated not only by least-squares methods but also by maximum-likelihood for example. As regards ...
• 31.9k

### What's the use of '% to GDP' type of variables?

Imagine that I am trying to determine whether eating corn has any effect on your height. I see that in the US, total corn consumption is 20 million tons per year (made up number, all others will be ...
• 26.2k

### How to find $\phi$, that denotes the correlation of signals among informed traders?

A degenerate joint normal is distribution is one in which you cannot find a PDF for the distribution. They assume you can. (The covariance matrix is invertible). Let $f(s_1,s_2\dots,s_n,v)$ be the ...
• 1,829
Accepted

### What should we do if the subsample have the opposite results to the general results?

I'd interact the regressor you are interested in with a dummy for the country being developed and see what happens. Its entirely possible that the mechanisms at play in developed contries are ...
• 1,248
Accepted

### How to recognize correlation in spurious regression case

Just regress Y on X: $$Y=b_0+b_1X+ e$$ and you will likely find some negative significant $b_1$ coefficient even though both series are just unrelated random walks. You can also see that as one series ...
• 42.3k
Suppose the relationship between $y_{i,t}\equiv\log w_{i,t}$ and $z_{i,t}\equiv\left(s_{i,t},j_{i,t},e_{i,t},x_{i,t}\right)^{\top}$ is given by $$y_{i,t}=g\left(z_{i,t}\right)+\varepsilon_{i,t},$$ ...