Dr Gianluca Baio has been selected as one of the co-chairs of the Missing Data in Observational Health Economics and Outcomes Research (HEOR) Working Group, a working group of the Statistical Methods in HEOR Special Interest Group (SIG) of the International Society for Pharmacoeconomics & Outcomes Research (ISPOR). ISPOR’s leadership group has expressed the view that there is a need to translate the most advanced research in those areas into a guidance report within the HEOR space. Reporting criteria and checklists for clinical trials and observational studies will encourage researchers to discuss the extent of missing data and the analytic approaches used. Therefore, the goal of this project is to provide recommendations about identification and reporting of missing data (and tempering conclusions in light of missingness) as well as guidance on current methods for handling missing data, specifically focusing on situations and applications that are relevant to HEOR.