Any analysis of the promise "unemployment in the district will go down by Y%" will be worse than useless, because politicians have little control over the unemp

Any analysis of the promise "unemployment in the district will go down by Y%" will be worse than useless, because politicians have little control over the unemployment rate. You would be judging them based on a coin flip. You have to include the quality of the initial promises. As for modeling the effect of policy on the real world, lots of people already try to do this, and their results do not agree. It's a very hard problem, perhaps impossible.