Research findings show that in developed countries where some ethnic groups are substantially less successful than the majority population, there are bias, disparities, and disparate-impact policy dilemmas endemic to these societies. On the basis of the experiences of Western European immigrants to Canada and the United States early in the 20th century, it has often been asserted that first-generation immigrants are typically more law-abiding than residents, with higher crime and imprisonment rates in later generations. To some extent, contemporary research has validated this traditional model; however, recent research has shown this model to be simplistic and only partially accurate. One reason is that self-selected economic migrants from many Asian cultures have lower crime rates than the resident population in the first and later generations. The traditional model does not account for many groups deriving directly and sometimes indirectly from South and East Asia. A second reason is that this model does not sufficiently take into account the cultural differences between groups that differentially affect adaptation. Third, the model does not adequately account for differences in receiving countries' social welfare (and settlement) policies. Research in Sweden, for example, shows that Swedish social welfare has reduced the "second-generation effect." Fourth, why groups migrate powerfully shapes criminality and indications of successful adaptation; and fifth, the traditional model does not describe the experiences of many immigrant groups that have economic or social characteristics that fundamentally shape predicted criminality. The next step for research is suggested.