There is a push in Congress to expand visas for highly skilled immigrants, which would be very good for the economy. Unfortunately, some lawmakers seem determined to expand high-skills visas at the expense of family visas, which are already subject to sharp quotas.

Their logic is easily grasped: A study by the American Enterprise Institute and the Partnership for a New American Economy found that a foreign-born worker with an advanced U.S. degree in science, technology, engineering or math creates, on average, 2.62 U.S. jobs. Between 1995 and 2005, immigrants helped start more than a quarter of U.S. technology and engineering companies.

What is less appreciated, however, is the crucial role that stable families play in helping immigrants acquire an education, hone skills, build businesses and create jobs. Under current law, family immigration quotas are segmented into half a dozen categories. Unmarried adult children of a U.S. citizen, for example, enjoy a higher preference than a permanent resident’s adult children or a citizen’s siblings. The quotas for the respective categories vary, as do the wait times.

Individual country quotas impose even longer waits for family members seeking to emigrate from nations where demand is high. It can take two decades or more for a sibling from the Philippines to immigrate, for instance. All told, more than 4 million people are caught in the family-immigration backlog.

There is a paucity of research on the economic effects of such immigration, in part due to privacy concerns and in part due to the inherent difficulties in measuring such things. As a 2007 White House Council of Economic Advisers memo noted, “This is because immigration’s economic impact is complex and may play out over generations, and because not all natives are alike in terms of their economic characteristics.”

As Congress grapples with the need for a new immigration policy, it’s worth keeping in mind that family immigration has its own value, economic as well as social. Immigrant families who pool resources to succeed are often engines of economic growth, especially in blighted neighborhoods where new small businesses are both inexpensive to establish and vital to community survival. Newly arrived Korean grocers in New York anchored many neighborhood recoveries in the 1980s as the city struggled to overcome epidemics of drugs and crime.

Research suggests that immigrant spouses upgrade their occupations over time, partially closing the gap with immigrants whose visas are employment-based. Similarly, immigrant family members often support one another financially, providing both capital and labor for entrepreneurial efforts.

“Our experiences in the field suggest that the family is often the main social organization supporting the establishment and operation of a small business,” said University of South Carolina sociologist Jimy Sanders in Senate testimony.

What’s more, when immigrants have their families with them, as the Asian American Justice Center points out, they “invest their earnings domestically to build their lives in America” rather than sending remittances abroad.

The Obama administration in January created a waiver designed to ease immigration obstacles for some families. The White House has also proposed temporarily increasing annual visas to “eliminate existing backlogs in the family-sponsored immigration system.” But unless the quotas are raised, the backlogs will soon reappear.

There is no way for the U.S. to accommodate everyone who wishes to live here. But reducing family visas would exacerbate personal hardships while foreclosing a pathway to opportunity that is essential to the American story. Yes, we need more math and science Ph.Ds, and we should adjust our immigration policy accordingly. But America was built not just by an educated elite but also by men and women who arrived with little and created much.

Yahoo founder Jerry Yang didn’t immigrate to the U.S. as a highly skilled entrepreneur; he came as a child. So did Google co-founder Sergey Brin (albeit as the child of a Russian mathematician). Yet the economic impact of both men has been profound. The U.S. needs high-skills, low-skills and family immigration, each of which contributes to economic growth and the American character.

Bloomberg News (March 18)