Journal article: This article presents the methods and preliminary findings from IMPALA, a database that systematically measures the character and stringency of immigration policies. Based on a selection of data for six pilot countries between 1990 and 2008, we document the variation of immigration policies across countries and over time. We focus on three specific dimensions: the number of entry tracks for economic workers; the measurement and role of bilateral agreements that complement unilateral immigration policies, and aggregation procedures that allow for gauging the stringency of immigration regulations comparatively.