Project Harmony is an NIAAA-funded project that uses Integrative Data Analysis (IDA), meta-analysis of individual patient data (MIPD) and propensity score weighting to assess variation in treatment effect sizes across (up to ) 50 RCTs geared towards treating comorbid PTSD and AOD (Alcohol and Other Drug) disorders. In this colloquium, we explore critical issues in the conduct and execution of an IDA study focused on treatment outcomes. We then give an overview of a series of papers developed in the first 18 months of the project that center around the use of item response theory (IRT) analysis as a method of incorporating “symptom weighting” in the scaling of PTSD severity using data from the NIDA CTN Women and Trauma study. Finally, we introduce the concept of the “Platinum Standard” for PTSD nosology and explore initial findings from an IDA analysis of 7 studies that are a part of Project Harmony.