What falsifiable metric could be used to say Trump was successful by his own and by Republican aims?
Things he claims
1. Better healthcare. Cover Everybody, cost less and have lower deducables
2. More GDP Growth. Obama never had a year of 3% economic growth. "Obama is the first president in modern history not to have a single year of 3 percent growth. If Trump can deliver an average of more than 3% over his 4 years in office I think an impartial observer would agree the economy has done well.
3. A balanced Budget.
4. Infrastructure improvements are a big part of Trumps promise. These are measured here
Carbon emissions I would like to see improve or not get worse but Trump did not campaign on improving. If Carbon emissions increase as predicted Trump is only doing something he has campaigned on doing.
There are many things like this but by picking a small number of things that they claim will improve I want to make a easy to check test.
Trump and the Republican party aim to deliver 3%+ Growth. A healthcare plan that covers more people and reduces deductibles. Improved infrastructure. And a budget position that is improving. If they do not do this by their own terms they have not succeeded.