Accurately identifying English-language learner (ELL) students who also need special education services has long been a problem for educators. Historically, English-learners were overrepresented in special education, but litigation and civil rights complaints have, in more recent years, led to an equally troubling problem with identifying too few ELLs with legitimate special education needs, or not providing services to them in a timely manner. National research done within the last decade, including a 2003 study commissioned by the U.S. Department of Education, found that overidentification occurred more commonly in districts with small numbers of ELLs (fewer than 99 such students), and underidentification was more common in districts with larger ELL populations. More recent data, however, seem to suggest that underidentification might be the larger issue on a national level: In 2009-2010, English-learners comprised 9.7 percent of students enrolled in public schools, but made up 8.3 percent of public school students being served under the Individuals with Disabilities Education Act, according to the National Center for Education Statistics. And by 2030, English-learners will comprise an estimated 40 percent of the American student population. The heart of the problem, educators and researchers say, is discerning whether students are simply struggling with acquiring English or truly have disabilities that are impeding their progress. It's a challenge that the Education Department is trying to help districts tackle, starting off by commissioning an exploratory study of a half-dozen districts that will document, in detail, the procedures and techniques that educators are using to identify English-learners for special education. Among students with disabilities, "there seems to be evidence in some areas of overrepresentation of English-learners, and in some areas of underrepresentation of English-learners." Educators say that it is often hard to validly identify students and disentangle the disability from the language problems. One of the difficulties is that so many of the assessment and evaluation tools for determining whether students have disabilities are intended for students who speak a single language, usually English, and who are proficient in it.