Suppose I ran the following R code:
plm(Y ~ X1 + X2, data = df, effect = "twoways", model = "within", index = c("country", "year"))
That is, I have panel data and am using the plm package.
Which type of standard errors am I getting from the code above if I do not adjust anything else? Is it
- homoskedastic standard errors,
- heteroskededastic-robust standard errors
- heteroskedastic-robust and clustered standard errors,
- something else?