Abstract
Proposals for a patient centered core impact set (PC-CIS) are of little relevance to formulary and health system decisions, let alone patients and providers, unless the elements included in the data set meet the standards of normal science and fundamental measurement. Adhering to these standards will have the effect of focusing on the adequacy of proposed core impact measures, with a filter in place to accept only those that meet the standards not only of the physical sciences but also mainstream economics. and health economics. Fortunately, we are well aware of what the criteria for acceptance and rejection of the core impacts within disease states should be in terms of their required attributes and their relevance for supporting evaluable value claims, notably for patient reported outcomes, Rasch or modern measurement theory. Care must be taken to delineate the core impact elements: separately identifying those that are purely clinical from core patient centric impacts, which is turn should be separated from impacts defined in terms of drug utilization and resource utilization. The purpose of this brief commentary is to set out the required standards for core impact patient-centric value claims and the framework for evaluating those claims. The critical issue for patient-centered core impacts is to recognize the constraints imposed by the standards of fundamental measurement for target patient populations within disease areas; unless these constraints are recognized we will fail. The leads to the role of Rasch or modern measurement theory calibration as the framework for patient centric measures of latent traits or attributes. From these perspectives PC-CIS is premature; until we have agreed standards for measurement for the impact or outcomes for clinical, patient-centric and resource utilization as a core set of disease specific instruments, it seems pointless to push forward to a wider scope when the present evidentiary foundation is so weak.