I am still a bit confused by this proposal to examine clinical trial and observational data from multiple sources to identify the common data elements needed/used to evaluate medications used to treat HIV/AIDS. The investigators’ goal, to develop recommendations on the optimal data representation format that allows data scientist to easily integrate HIV research datasets across studies, is laudable. But the research proposed here lacks clarity. They are going to do frequencies for every data element collected for 6 trials of HIV/AIDS therapies available for re-analysis on the YODA Project platform, and compare to the frequencies observed for data elements collected from a host of other studies using Electronic Health Records (EHR) and claims data from CMS and the Greater Plains Collaborative, as well as the Lung HIV study from the National Heart Lung and Blood Insitutetrial platform, studies from the National Institute of Allergy and Infectious Diseases HIV Trial Networks, and multiple still to be determined clinical trials from Vivli and clinicalstudydatarequest.com? I still don’t see why access to IPD are necessary for this proposal, as provision of blank CRFs would allow the investigators to determine every data element collected. But if calculating frequencies is key to this research – and the authors reference to NLM-based informatics research of this type suggest that it is – then that seems ok.