The community manager of a large developer community recently mentioned to me that we now have the ability to roll out badges for achievements on the site. These sound similar to Stack Exchange's badges (SE is not the platform); users would gain badges for positive contributions, ranging from a "nice post" badge for a single post that's well-received to badges that recognize good contributions over time. There is not currently a reputation system; the badges would be the only visible gamification, though user profiles link to all their contributions so you can get a sense of how active they've been.
I've heard some people in other professional communities dismiss badges or "achievements" as "gold stars, like in kindergarten", arguing that it's not very professional. I've heard others argue that badges help user engagement and keep people around and active longer. I'm aware of this list of research papers about Stack Exchange/Stack Overflow, on which I found this paper about badges, which talks about badges and reputation. I don't know enough statistics to be able to tease out the badge-only effects from what they report there. And, of course, it may be just plain hard to measure the effects of one reward in a multi-reward system like SE.
How can we evaluate the option of badges, without a scoring system like reputation, for our own community, other than trying it and seeing what happens? Is there any research, or maybe case studies, that could help us predict the effects of introducing badges to our community?