This is an interesting 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. My only caution is in wondering whether access to IPD are necessary for this proposal. Wouldn’t provision of blank CRFs, used to collect data throughout the trials during the multiple points of follow-up, be sufficient? The investigators do not need to use the actual data; instead, they need to examine what data were collected and how those data were categorized.