Experts study immigration in relation to jobs, crime and disease

According to the U.S. Census Bureau, immigrants made up 13.9% of the total population in 2022. Among them are highly skilled workers who fill critical gaps in high-tech industries as well as those who construct the buildings in which we live and who plant and harvest the foods we eat. Some arrive seeking greater opportunity while others bring hope simply for a life free from persecution and poverty.

In every country and context, immigration is as much a force for shaping society as it is a flashpoint for anger and prejudice. At the same time, research shows that immigrants make important contributions to their new countries.

"Immigrants are part of the fabric of a country's economy and society," said Giovanni Peri, director of the Global Migration Center and a professor of economics at UC Davis. "We want to bring more information, clarity, facts and discussion to shine the light that immigrants are human beings who bring assets with them to their new countries."

Immigration and jobs

In the U.S., the negativity associated with immigration is partly driven by the idea that immigrants are a threat to jobs. For nearly 30 years, Peri has published papers on how immigrants affect jobs and wages for everyone in the U.S. For a 2006 report for the American Immigration Council, Peri analyzed over a decade of economic data to understand the dynamics of how immigrant workers shape local job markets.

Instead of revealing a zero-sum game in which immigrants and native-born workers compete for a limited number of jobs, the analysis found a net positive effect on native-born workers. The study found that immigrants did not drive down wages, as is often argued.

From 1990–2004, immigration increased wages by as much as 3.4% for the 90% of native-born workers with at least a high-school diploma. For those without a high-school diploma, immigration caused a loss of 1.1% percent of their yearly wages.

The analysis also showed how these effects on wages are possible. Immigrants bring levels of education and skill sets that complement—rather than compete with—the native-born workforce.

An April 2024 NBER paper by Peri and co-author Alessandro Caiumi confirm that these findings remain true nearly 20 years later. With improved statistical methods, this new analysis found that immigrant workers at all skill levels either have no effect on jobs and wages for U.S.-born workers or that they generate a slight improvement.

"Instead of a threat to native-born workers, immigrant workers bring with them skills and levels of education that are complementary," said Peri. "Instead of generating more competition across the board, immigrant workers have almost always increased overall economic opportunity for everyone."

The myth of immigrants and higher crime

Economics research has also found the idea that immigrants drive higher crime rates to be a myth. A recent study co-authored by Santiago Pérez, an associate professor of economics and Global Migration Center affiliate, analyzed over 150 years of U.S. Census Bureau data to compare the incarceration rates of immigrants and the U.S.-born.

The study found that immigrants have had a lower incarceration rate than the U.S.-born in every single year since 1870. Also, since the 1960s, the gap in incarceration rates has significantly grown. In recent years, that gap has reached 30% overall.

The team explored a number of potential explanations for this shift that began about 60 years ago. One might have been that deportation was removing more people from the country before they could be counted by the U.S. Census. However, mass deportations in the U.S. began in the early 2000s, well after the incarceration trends for immigrants and the native-born began following different paths.

In fact, the data might be overestimating the rates at which immigrants commit crime. The U.S. Census Bureau does not include any reference to their crime. Even if the only law they broke was entering the U.S., they are still reported as an incarcerated individual along with others who have committed violent or property crimes.

"People often see past migration waves in a more positive light," said Santiago Pérez, an associate professor of economics and Global Migration Center affiliate. "They think about Europeans who came in the late 19th century and early 20th century, and they tend to contrast this with new migrants, but what we find in the paper is actually the opposite."

Global migration, disease and stigma

Migration is by all measures a global phenomenon. About 2.3% of the global population, about 184 million people, could be considered migrants for having left the country in which they were born to live in a new nation without citizenship. According to the United Nations High Commissioner for Refugees, or UNHCR, 36.4 million of these in 2023 were war refugees.

When large numbers of people end up in refugee camps, disease is more likely to spread. Disease itself can attach added stigma to a person's status.

"Communicable diseases already are quite stigmatized, and there's this historical association pinning a communicable disease or an outbreak with immigration," said Angel Desai, an assistant professor at UC Davis Health and a member of the Global Migration Center executive committee.

Desai is a physician and infectious disease specialist who conducts research on global public health. In a recent study, she and her co-authors looked at outbreaks of hepatitis E, an infection that affects the liver. With roughly a decade of data on outbreaks in refugee camps across a number of African countries, they found that these outbreaks were always associated with crowding, poor sanitation and a lack of infrastructure like running water and sanitary waste disposal systems.

"These outbreaks were not inherent to the population," said Desai. "Hepatitis E flourishes in situations where you have poor sanitation and a lot of crowding."

In another study, she and her co-authors analyzed how U.S. news media portrayed tuberculosis and immigrants. Their analysis showed that the political leanings of news media outlets drove differences in the number of reports they published on the topic.

"Communicable diseases don't care where you're from," said Desai. "We need to look deeper into the structural and environmental causes of these diseases and really be making sure that our policies help everybody achieve the best health outcomes as opposed to using them as a tool to further stigmatize a group of people."