Before accepting their promises of "efficiency". Like if the mayor of a city says that they can lower taxes because of inefficiences in gov't. Of course they won't give details because their competitors will steal it. BUT you can get a sense from their previous actions/and how they view/perceive the world.
1 possibly-related/prominent example: 1st bush - "Read My Lips; No New Taxes".
The fault here is that they don't know the situation before they make those comments. Rather, we should analyze their fundamental understanding of the workings of the state.