1. The code stops with an error message. What should I do?
Most problems can be solved by exactly repeating the following steps:
a) close your Stata and reopen it
b) type: "update all" (and if asked "update swap" to fully install newly updated executables)
c) type:
net from "https://web.stanford.edu/~jhain/Synth"
net install synth, all replace force
In most cases the code should run now.
2. When installing the program using net install I get the following error message:
Could not load plugin: c:\ado\plus\s\synthopt.plugin
(error occurred while loading synth.ado)
This means that a plugin is not availbale for your platform (see here details). In this case you can download the C code to compile the plugin on your platform here.
3. How can I improve the fit for the pre-treatment ouctomes?
Use the "nested" and the "nested allopt" option. Also try to add more pre-treatment years of the ouctome variable. Finally, trim the donor pool to units that are sufficiently close to the treated unit.