This study analyzes which factors are associated with individuals’ decisions to start participating in the Supplemental Nutrition Assistance Program (SNAP) and with decisions to leave the program during the period 2004 to 2006. Based on data from the U.S. Census Bureau’s Survey of Income and Program Participation (SIPP), the study uses a technique called “multivariate regression” to isolate the impact of various factors associated with participation decisions while holding other factors constant. The factors examined in this report include individual demographic and economic variables, as well as State economic conditions and policies. This report is a companion to Dynamics of Supplemental Nutrition Assistance Program Participation in the Mid-2000s.