The Food Stamp Program serves as the foundation of America’s national nutrition safety net, the first line of the Nation’s defense against hunger, and a powerful tool to improve nutrition among millions of low-income families and individuals. Because the program has such a central role in the national nutrition safety net, there is keen interest in tracking its performance over time and across areas. While there are many aspects to the program’s success, one key performance outcome is the extent to which it reaches the people it is intended to serve. The Food and Nutrition Service (FNS) and other researchers have used a variety of approaches to calculate food stamp participation rates. While different approaches can look similar in concept, the results – for particular States or for the Nation as a whole – can often look quite different. These differences can be confusing for users who seek to describe the success of the Food Stamp Program without becoming experts in statistics and data analysis. This paper provides an overview and comparison of two sets of estimates produced by FNS as indicators of Food Stamp Program performance.