Over the past several months, the debate over immigration, crime and ? most recently ? the policy of removing children from parents detained for illegally crossing the U.S. border, has raged across America. As professors and social scientists, we?ve watched this debate with some dismay, as facts on immigration have too often been overtaken by opinions and politics. So we want to share some facts we have learned through years of research. While we understand the political arguments made for and against various immigration policies, our job as scientists is to objectively evaluate the data used to support various policies and stances and use research to more accurately predict the consequences of our actions. And what we know is this: Particularly as it relates to illegal immigration at the U.S. borders, the research does not indicate that there is a growing illegal immigration problem, or that immigrants commit more crime. In fact, it consistently shows the exact opposite. We?ll explain it all in a minute. But first, why should you listen to us anyway? Whether we are developing new tools to help law enforcement effectively prevent crime, evaluating offenders or determining the risk factors for criminal behavior, we always depend on the data to drive our conclusions. The widespread support and use of criminological research, particularly by the law enforcement community, is an indicator of our unbiased and evidence-based approach to research and policy. We let the facts speak for themselves. To that end, here are raw data and findings of recent research on immigration, particularly as it relates to crime. How many illegal immigrants live in the United States? According to the Pew Research Center, in 2016 there were an estimated 11 million illegal immigrants living in the United States. Other organizations, such as Center for Migration Studies, show similar estimates. The number of illegal immigrants, which represents about 3 percent of the current total U.S. population, has remained consistent for almost a decade, suggesting that there is not a dramatic increase in immigrants arriving illegally into the country. Data from other sources confirm this. Specifically, estimates from a number of politically diverse think tanks suggest that there are roughly 300,000 new illegal immigrants entering the United States every year. This reflects a sizable decline from the nearly 1 million new entrants who were arriving illegally in the early part of the 21st century. Not border arrests, but visa overstays. Numbers from U.S. Customs and Border Protection tell a similar story: Border patrol arrests have trended steadily downward over the past two decades, from about 1.6 million arrests in the year 2000, down to approximately 300,000 arrests in fiscal year 2017. (On the border of Mexico in Texas, Border Patrol agents made 34,057 arrests last month.) Data also show that arrests for illegal border crossings decreased 25 percent from 2016 to 2017. Further, the Office of Immigration Statistics, the federal agency tasked with examining the issues associated with immigration, recently noted that since 2000, there has been a 90 percent drop in illegal border crossings. In contrast, U.S. Department of Homeland Security data suggest that more than 600,000 people overstayed their visas in fiscal year 2016. That figure is more than double the rate of those who entered the country illegally at the border. The Center for Migration Studies also indicates that those overstaying their visas accounted for roughly two-thirds of the new illegal immigrant population in 2014. What about crime? There seems to be a public perception that illegal immigration increases crime. The research simply does not bear that out. With very few exceptions, research consistently shows that immigrants commit fewer crimes on average than native-born Americans, and that cities and neighborhoods with higher immigrant populations experience lower crime rates. This holds true when looking at legal or illegal immigrants. A recent report from the libertarian Cato Institute found that illegal immigrants in Texas have substantially lower rates of arrest or conviction than native-born Americans for homicide and larceny. Legal immigrants had even lower crime rates than illegal immigrants and native-born Americans. Using data from all 50 states and Washington, D.C., sociologists Michael Light and Ty Miller examined if violent crime rates go up when the population of illegal immigrants increases. They found that violent crime rates fell with higher concentrations of illegal immigrants, even when other demographic and economic factors associated with crime were accounted for. In a different study, they showed that illegal immigration is associated with fewer drug and DUI arrests, and fewer drug overdose deaths. The evidence is so clear that immigrants do not commit more crime, researchers are now studying why crime is lower in immigrant communities in order to help address crime in other areas. Yes, but what about MS-13? Even with respect to the violent gang MS-13, data from U.S. Customs and Border Protection indicate that only a tiny fraction of illegal immigrants are members of the gang. Of the 310,531 aliens apprehended in fiscal year 2017, only 228 were members of MS-13. In other words, more than 99 percent of those entering the United States have no affiliation with the MS-13 gang. What is the effect on children separated from their parents? Until last month, a "zero tolerance" policy backed the separating of children of illegal immigrants from their families indefinitely. The research is clear on the downstream effects that are likely to occur from such actions. Being separated from their parents is a traumatic event for most children, and research consistently shows that it has a negative impact on a child?s future health, behavior and psychological development. Decades of research conducted in the medical and psychological fields consistently shows that acute trauma in childhood, such as being involuntarily separated from one?s parents for days or weeks on end, causes permanent changes to the developing brain, and that this trauma may have many severe, negative effects on the child?s health, psyche and behavior. As the American Medical Association stated in its open letter on family separations, adverse childhood experiences such as being separated from one?s parents dramatically increases the risk of serious and life-threatening ailments in adulthood, which include heart disease, liver disease, high blood pressure, diabetes, obesity, chronic lung disease, bronchitis, emphysema, skeletal fractures, cancer and even early death. As noted in the American Psychological Association?s statement on the "zero tolerance" policy, children separated from their parents often suffer severe psychological distress. Research shows this trauma exponentially increases the risk of mental health issues including depression, anxiety, post-traumatic stress disorder, eating disorders, insomnia, substance abuse, and more. The longer the separation continues, the greater and more permanent the psychological and health effects will be. Given the serious long-term psychological and health effects on children who were involuntarily taken from their parents, the clear evidence-based strategy would be to reunite the children with their parents as quickly as possible (as each day increases the risk and severity of negative outcomes), and to never enact such a policy in the United States again. But they?re crossing illegally, right? On a legal note, it is important to point out that improper entry into the United States is a misdemeanor under federal law (8 U.S. Code § 1325), while overstaying a visa is technically a civil matter, not a crime. Comparatively, driving without insurance or a license, and driving more than 25 miles per hour over the speed limit, are also misdemeanors in Florida, all punishable by a fine or fewer than 12 months in jail. Nevertheless, those detained for illegally entering the country have a constitutional right (under the Fifth and 14th amendments) to due process, and the right (under Article I, Section 9) to have their case be evaluated by a judge or immigration officer (see also 8 U.S. Code § 1229). The U.S. Supreme Court ruled that these rights are offered to all those on U.S. soil, regardless of citizenship status. This means all peoples under American jurisdiction have the fundamental right to due process and to challenge their detention, including illegal immigrants. With respect to asylum, the United States abides by international law set during the 1951 U.N. Convention on Refugees, and the 1967 Protocol on the Status of Refugees. These laws were created after several nations (including the United States) failed to accept refugees fleeing the Nazis in the lead-up to, and throughout, World War II. This convention and its protocol made it illegal for nations to mistreat, endanger or deny asylum-seeking refugees their human and civil rights, regardless of immigration status. How does asylum work? It is true that asylum may only be declared at an official port of entry, which are located at specified airports, seaports and border crossings in the United States. In other words, asylum may not be granted or considered at locations that are not designated a port of entry, such as footpath routes like El Camino del Diablo (the Devil?s Highway, named for the perilous conditions) through the Sonoran Desert. According to CBP, there are currently 29 approved ports of entry in the state of Texas, among others in the southwestern U.S. What to make of it all? While we understand the politics surrounding immigration, it is our hope that an unbiased assessment of the data and research can be made by all Americans, and an informed and evidence-based policy that reflects the nature and consequences of the immigration debate can be made. Available evidence (1) does not support a link between immigration and higher crime, (2) indicates that attempted border crossings have declined substantially, (3) individuals overstaying visas contribute disproportionately to the illegal immigrant population, and (4) the forced separation of children from their families will have negative long-term implications for their health and development. We suggest that this evidence be taken into serious consideration by policymakers and the public as we work to address immigration in the United States. Michael Leiber, PhD, is professor and chair of the Department of Criminology at the University of South Florida. His research interests lie in race/ethnicity and juvenile justice decision-making. Lyndsay Boggess, PhD, is an associate professor in the Department of Criminology at USF. Her research focuses on community characteristics and the geographic distribution of crime. Bryanna Fox, PhD, is an assistant professor in the Department of Criminology at USF. Her research examines the psychology of criminal behavior and development of evidence-based tools for law enforcement. Richard K. Moule, Jr., PhD, is an assistant professor in the Department of Criminology at USF. His research examines offenders, technology, and police. This article reflects the author?s own research-based views and not necessarily the institutions with which they are affiliated.