How P4P can be dangerous if implemented poorly:
The hubris,arrogance and naivete that I believe characterize those who make rules for how to treat individuals based solely on group data ignoring the input of the physicians on the scene is even worse that the folks who simplistically sprout out coarse grain outcome data quality indicators such as percentages of patients with HbA1c less than 7 %. In the later they are just counting beans in the former they are making rules about treatment decisions that might be determinative of the outcome. It all seems to be part of the notion that medicine is too important to be left to the individual physicians and patients.
