Conjecture

Attached credit makes people contribute, and contribute better, because it closes the gap Ostrom found at the boundary of a commons: where "any benefits they produce by their efforts will be reaped by others who have not contributed to those efforts", investors get less than they expected and the game slides toward a one-shot dilemma. Her monitors also worked partly for credit: "The individual who finds a rule-infractor gains status and prestige for being a good protector of the commons." Credit attached to a named, checkable change does two jobs at once: it pays the contributor, and it makes the contribution inspectable, so credit for wrong work becomes a liability rather than a gain. That the second job raises quality and not only volume is Rio's step and untested here.

Keeping power in check