Has there been any research done that contrasts point-based and achievement-based gamification methods? Stack Exchange is a good example of these two methods of gamification:


Reputation
Badges


I am curious as to whether there has ever been any research done that defines and contrasts these methods?  I am specifically interested in discovering what sort of goals and behaviors collecting achievements encourage as opposed to collecting points.  How do end-users respond differently to these methods?  Or do they?

Taking Stack Exchange as an example, we could ask what sort of behaviors are we attempting to encourage with reputation as opposed to badges that require them to be separate entities?
Reputation is a recognition system for participation, while the badges represent the type of participation.

Reputation amasses over time simply by recognizing that the individual is participating in a meaningful way, and that their experience can be judged by the amount of reputation. Badges, on the other hand, show where their aptitude and participation lies (Such as being a prolific editor, having insightful answers, etc.)

Both of these will appeal to people in different ways, and both will contribute to a thriving site, as it encourages several levels of participation. The reputation will be more of a benefit system, as you get increasingly advanced privileges on the site for higher reputation, and the badges are the "pat on the head" motivation.

While I don't have access to the full text, the precis for this article suggests that they presented specifically on the Stack Exchange model, and the badge/reputation system as applied to an online community. Other than that, most of the gamification models that I found searching scholarly articles were more geared toward education and social media rather than Q&amp;A type sites.