External Validity and Model Validity A Conceptual Approach for Systematic Review Methodology

Background. Evidence rankings do not consider equally internal (IV), external (EV), and model validity (MV) for clinical studies  including complementary and alternative medicine/integrative health care (CAM/IHC) research.This paper describe this model  and offers an EV assessment tool (EVAT©) for weighing studies according to EV and MV in addition to IV. Methods. An abbreviated  systematic review methodology was employed to search, assemble, and evaluate the literature that has been published on EV/MV  criteria. Standard databases were searched for keywords relating to EV, MV, and bias-scoring from inception to Jan 2013. Tools  identified and concepts described were pooled to assemble a robust tool for evaluating these quality criteria. Results. This study  assembled a streamlined, objective tool to incorporate for the evaluation of quality of EV/MV research that is more sensitive to  CAM/IHC research. Conclusion. Improved reporting on EV can help produce and provide information that will help guide policy  makers, public health researchers, and other scientists in their selection, development, and improvement in their research-tested  intervention. Overall, clinical studies with high EV have the potential to provide the most useful information about “real-world”  consequences of health interventions. It is hoped that this novel tool which considers IV, EV, and MV on equal footing will better  guide clinical decision making.