Advancement professionals have always been thirsty for information that will help them understand how their programs compare with those of their peers. But in recent years the demand for benchmarking data has exploded as budgets have become leaner, leaders have become more business minded, and terms like "performance metrics and return on investment" have made their way into the campus lexicon. The challenge with benchmarking, however, is that not all advancement programs are organized, budgeted, and accounted for in the same way, making apples-to-apples comparisons problematic. This article presents the CASE Advancement Investment Metrics Study, or AIMS, developed by senior-level professionals to help their colleagues benchmark expenses and staffing in advancement using a common survey instrument. The AIMS survey is accompanied by detailed definitions of what to "count" as an expense regardless of how the advancement functions are structured or budgeted. (Contains 7 figures.)