Here is a link to an interesting article discussing the value of government performance audits.  Certainly this is an idea that should be pursued in appropriate circumstances, especially if it can be shown that the return is likely to be greater than the cost.  http://www.governmentauditors.org/images/stories/reports/EstablishAuditing.pdf 

I have had some experience with the Yellow Book Government Auditing Standards as the past audit committee chair for a large nonprofit.  I view the Yellow Book audit primarily as a compliance audit.  For example, in addition to meeting accounting and internal control standards, is the nonprofit in compliance with the funding source's requirements for measuring project attendance or use goals.  A performance audit appears to go at least one step farther, to specifically evaluate or help evaluate whether the project is meeting its intended objectives.   This would appear to add some accountability to government programs and funding.  At the initial stage, measurable objectives would be stated.  Subsequently, it would be evaluated whether or not those objectives are being met.  Project evaluation and re-evaluation would become more regular, and transparent.  Seems like a very good idea to me, depending on an analysis of likely economic benefit v. costs.