Test and train dataset: evaluate RMSE of my model

[Jannic Cutura]

suppose I run the following regression:

reghdfe y x1 x2 x3  if train == 1, abs(fe1 fe2) cluster(fe1)
predict pall
reg y pall if test == 1, nocons

Am I right in that the RMSE reported in the second regression is the RMSE of the true value (y) and what my model would have predicted (pall)?

[Phil Bromiley]

You didn't get a quick response. You'll increase your chances of a useful answer by following the FAQ on asking questions - provide Stata code in code delimiters, readable Stata output, and sample data using dataex.

I'm not sure you need the reg. If you have a predicted value and y, you can easily calculate rmse.