I am trying to combine two datasets - each datafile contains data for two countries and each file contains different observations. I wish to combine them into a single file in order to run a pooled country model for the four countries.

I found this website helpful http://www.cpc.unc.edu/research/tools/data_analysis/statatutorial/example9

and the stata manual (p. 388) describes one-to-one merges but I am unsure how to proceed.

I would be grateful for any advice you could give. Thank you