Heated debate surrounds the topic of immigrants and their access to citizenship. But Stanford research shows naturalization acts as a catalyst that builds greater social and political integration for these immigrants and their new countries.

A new study by Stanford political scientist Jens Hainmueller in Proceedings of the National Academy of Sciences shows how citizenship can strengthen social and political bonds. His research focused on Switzerland, which currently has a very high number of immigrants relative to population size, with many of them marginalized socially and politically.

As Hainmueller noted, one in four residents of Switzerland is a foreigner, and a considerable anti-immigration sentiment exists in the country.

"Understanding the effect of naturalization on long-term integration of immigrants is an important question in light of these problems," says Hainmueller, co-director of the Immigration and Integration Policy Lab and faculty affiliate of the The Europe Center.

Impact of Citizenship

To conduct this study, Hainmueller and his collaborators, Dominik Hangartner and Giuseppe Pietrantuono from the Migration Policy Lab at the University of Zurich, used a natural experiment in Switzerland that allowed them to uniquely isolate the effect of naturalization. Between 1970 and 2003, Swiss residents decided on individual naturalization requests based on secret ballot referendums, a practice shown to be highly discriminatory and no longer used. Applicants had to win at least 50 percent of "yes" votes to receive citizenship.

Hainmueller compared applicants who barely got accepted to those who were barely rejected. All applicants had similar characteristics, including educational background, financial stability and language skills. The difference between them was just a few votes, he says.

"It was luck if they got it or not," Hainmueller says, "similar to random assignment in a randomized experiment."

Nearly 15 years later, researchers tracked down the immigrants who faced these votes. It took almost two years to conduct over 750 personal interviews – they got a 45 percent response rate. According to the results, those who became citizens were integrated much better socially and politically.

To determine political integration, Hainmueller asked the study participants questions regarding information on the current president and if they voted. Immigrants who gained citizenship voted at the same rate as rooted Swiss natives. They also had the same political knowledge as rooted natives, if not more.

Hainmueller and his team also asked the immigrants a series of social questions. Compared to immigrants who did not earn citizenship, those who were naturalized were more likely to read the Swiss newspaper and not a foreign newspaper. Naturalized immigrants were also more likely to express the desire to stay in Switzerland long term.

Results from the study indicate that more socially marginalized groups, such as immigrants from Turkey and the former Yugoslavia, or those with less education, benefited the most from naturalization.

"This is what you would hope," says Duncan Lawrence, executive director of the Immigration and Integration Policy Lab. "Those groups that are more negatively affected benefit the most from naturalization."

Although this study did not examine why naturalization increased political integration, Hainmueller suggests it is related to becoming a more active participant in the democratic process.

He and his colleagues plan to expand this work to measure the impact of naturalization in other European countries and the United States.

Immigrants in America

In recent decades, immigration has increased across Western countries. In 2013, 41.3 million immigrants lived in the United States. In September, the Obama administration announced the Stand Stronger Citizenship Awareness Campaign, which is a new campaign that encourages the 8.8 million eligible immigrants to take steps toward citizenship.

"But nobody really knows what the impact of naturalization is in the United States because immigrants self-select into becoming citizens. If you simply compare naturalized and non-naturalized immigrants as most studies do, it is like comparing apples and oranges," Hainmueller says.

To answer these questions, Hainmueller and his team have designed a study to evaluate the impact of naturalization on immigrants in the United States. He plans to set up a lottery in which people can win a fee voucher to cover the cost of application fees ($680), which provides a financial encouragement to apply. Then he can make comparisons between those who won the lottery and became naturalized to those who did not.

The Immigration Lab is looking at a whole array of policies and programs that affect various types of immigrants, including refugees, undocumented immigrants and long-term residents. The next step is systematically analyzing the economic impact of naturalization, Hainmueller says. He hopes this work can provide evidence to inform policymakers, practitioners and advocates leading to more evidence-based policy-making.

This research was supported by Stanford's Immigration and Integration Policy Lab, which is part of the Institute for Research in the Social Sciences. The research was funded by a grant from the Swiss National Science Foundation.

Jens Hainmueller is a courtesy professor of political economy at Stanford GSB and an associate professor in the department of political science at Stanford’s School of Humanities and Sciences.