Is there something like GiveWell for government programs?

Sorry if this has already been asked. I’ve done several searches on this forum and elsewhere, but can’t seem to find anything. I’m interested in how cost-effective government spending is. I’m assuming paying taxes in most countries would be less effective than donating the same amount to GiveWell’s top charities, but I’ve yet to come across solid numbers to back up that conclusion. Has anyone put a dollars per life saved number on paying taxes?