Academics and policy makers require a better understanding of the variation of policies that regulate global migration, asylum and immigrant naturalization. At present, however, there is no comprehensive cross-national, time-series database of such policies, rendering the analysis of policy trends across and within these areas difficult at best. Several new immigration databases and indices have been developed in recent years. However, there is no consensus on how best to conceptualize, measure and aggregate migration policy indicators to allow for meaningful comparisons through time and across space. This article discusses these methodological challenges and introduces practical solutions that involve historical, multi-dimensional, disaggregated and transparent conceptualizing, measuring and compiling of cross-national immigration policies. Such an approach informs the International Migration Policy and Law Analysis (IMPALA) database.