To hear many anti-immigration groups tell it, people who move to the United States from abroad these days are a pretty sorry lot.

Immigrants, these groups say, come here to suck up free social services, not to better themselves. If they do work, they steal jobs from Americans and increase unemployment.

They bring all kinds of diseases with them, and once here they despoil the environment for native-born Americans. To many people, these kinds of statements have the ring of truth.

But studies from an array of groups — from the conservative Cato Institute to the liberal National Immigration Forum to the nonpartisan National Academy of Sciences — give the lie to these unfounded allegations.

Here is the truth about some of these myths:


MYTH: Immigrants use more government services than they pay for with their taxes.

REALITY: Actually, the National Academy of Sciences found that the average immigrant annually contributes $1,800 more in taxes than he or she receives in benefits. Over their lifetimes, immigrants and their children will each pay an average $80,000 more in taxes than they will receive in local, state and federal benefits combined.

Because states provide most services used by immigrants, they can be net financial losers, while the federal government is typically a net gainer.


MYTH: Immigrants increase unemployment and reduce wages.

REALITY: In line with a number of other studies, the Cato Institute found that immigrants do not increase joblessness, even among the lowest-paid workers. The institute studied the relationship of unemployment and immigration between 1900 and 1989 and found "no statistically reliable correlation" between the two.

Other studies have found that immigration either has no effect on wage levels or, at worst, a very slight effect on a very small number of the lowest paid jobs in high-immigrant areas.

There is a consensus among business leaders that immigration is vital to maintaining economic growth. Federal Reserve Chairman Alan Greenspan said recently that immigration is critical to mitigating "inflation pressures."


MYTH: Immigrants bring disease.

REALITY: Even though most immigrants come from countries poorer than the United States, recent immigrants are healthier than the U.S.-born population in virtually every particular.

The Cato Institute also found that general health indicators like birth weight and infant mortality are better among babies born to immigrants than to U.S.-born mothers.


MYTH: Immigrants degrade the environment.

REALITY: Since 1965, when the current high levels of immigration began, there is no evidence that the environment has worsened overall. In fact, many environmental indicators like air and water quality have generally improved.

The Cato Institute, citing the data's complexity, reported that it could not "prove a causal connection" between environmental problems and the number of immigrants entering the United States.