A new study shows the extent to which undergraduates are less likely to have any single institution that is alma mater.

Of students who received a bachelor's degree in 1999-2000, 59 percent had attended more than one institution, according to the report, from the National Center for Education Statistics. Bachelor's candidates who started at community colleges, of course, have always attended more than one institution. But the report notes that the multiple-institution trend has become quite strong among students who start at four-year institutions. Among such students, 47 percent of those who graduated in 1999-2000 had attended more than one institution.

Students who attend more than one institution don't necessarily transfer, the report says. A growing number of students "co-enroll" -- or take classes at multiple institutions, without necessarily leaving the institution at which they first enrolled. Nearly 11 percent of students who first enrolled in 1995-96 co-enrolled at some point in their college educations. The percentage was highest -- 13 percent -- for students who first enrolled at private colleges.

The report also found that transfers do not necessarily take place only once during a college career. Of the cohort of students who started in 1995-96, 25.9 percent transferred once, 5.7 percent twice and 0.5 percent three times.

The authors of the report write that it is important for colleges to pay attention to these trends because of correlations between some of these trends and completion rates. For example, of students who started at four-year institutions in 1995-96, those who never transferred were much more likely to have earned a degree or certificate within six years (72 percent) than those who transferred (45 percent).

And attending multiple institutions slows down degree completion. Of those who obtained bachelor's degrees in 1999-2000 and who started out at community colleges, those who attended just two institutions took an average of 8 years to earn a bachelor's, while those who attended more than two took an average of 11 years.

Of those who started at public four-year institutions, those who stayed at one institution earned their bachelor's in an average of 5 years, while those who attended two institutions had an average of 6 years, and those who attended more than two institutions took an average of 10 years. Of those who started at private four-year colleges, the figures are four, five, and nine years, respectively.