market role of female immigrants (Funkhouser and Trejo), a historical perspective on immigration (Carter and Sutch), a theoretical framework for addressing fiscal impacts of immigration (MaCurdy, Nechyba, and Bhattacharya), the association of immigration with criminal activity (Hagan and Palloni), and the theoretical labor market impact of international immigration and trade (Trefler). Many of the findings of these papers influenced the panel's final report, which was published in October 1997.¹ Revised versions of these conference papers are included in this volume.

In addition to these commissioned papers, the panel also decided to initiate some original research of its own. For its work on the fiscal impact of immigration, we relied on an ongoing study of New Jersey being conducted by one of the panel members (Garvey and Espenshade) and started our own case study of California (Clune). The final results from both case studies are also part of this volume. In addition to these annual budget estimates for two key immigrant states, the panel conducted a study of the national longitudinal effects of immigration (Lee and Miller). A part of that research project is included in this volume. Finally, the panel heard a series of presentations from an ongoing study of the effects of immigration on internal migration (Frey and Liaw). Internal migration is a central issue that arises in evaluating labor market impacts of immigration.

These essays served as important background for the NRC panel's deliberations and our final report. In addition, I believe that they stand on their own as scientific contributions on a critical policy issue not only in the United States but throughout most of the world. Because immigration touches sensitive issues and provokes strong emotional reactions, such dispassionate scientific research is all the more valuable.

Nowhere did our panel find the existing literature more lacking than on the fiscal effects of immigration. Although significant gaps remained, there were long and rich traditions of scholarship on the other two main questions—the economic and demographic impacts of immigration. Not so for the fiscal impacts. Instead, only a handful of existing empirical studies were available. Many of these represented not science but advocacy from both sides of the immigration debate. These studies often offered an incomplete accounting of either the full list of taxpayer costs and benefits by ignoring some programs and taxes while including others. More important, the conceptual foundation of this research was rarely explicitly stated, offering opportunities to tilt the research toward the desired result.