One thing I've been wondering about: it seems like building a massive amount of manpower for a campaign is (one of?) the most effective way to deploy campaign resources for voter persuasion. But it also seems presiding over a huge media budget is much more lucrative for senior campaign flacks. Is there an agency problem here?Yes.
OK, I'm tempted to just leave it there...I don't really know how cost-effective massive personal-contact voter persuasion (and GOTV) are compared with TV ads, but yeah, I think that there's a good chance that the self-interests of campaign staff and especially consultants is a problem. I'd also guess, however, that there's also a bias among candidates in favor of electioneering that they can actually see. Stories of billboard ads purchased only on the route from the airport to an incumbent, Washington-based candidate's house in the district are not completely apocryphal.
I'm not sure who if anyone has done work on this, however, so I don't know whether we have any idea of the effect. Remember too that a lot of the research by Don Green and others is relatively recent, and there's also a big status quo bias against innovation. I'll also link to an article I haven't read yet about it; it's a practitioners and political scientists roundtable and is likely very useful if you're interested in these questions.