For years, students from around the world have needed two things to be admitted and enroll at American colleges: a visa and an acceptable TOEFL score.
The latter -- the acronym stands for Test of English as a Foreign Language  -- is about as high stakes as a high stakes test can be. Colleges claim not to have automatic cutoffs for the SAT or ACT, but many institutions have no hesitation about setting absolute minimum TOEFL scores. The reliability of TOEFL is also high stakes for colleges. Many of the foreign students submitting TOEFL scores are applying to graduate programs, and admissions officers aren't just deciding whether to admit them, but are de facto deciding who will be TA's two or three years down the road, in front of classrooms of freshmen.
With more than 800,000 students taking TOEFL a year, the test is also of great importance to the Educational Testing Service, which is seeing its SAT exam facing criticism for embarrassing scoring errors  and a move by liberal arts colleges to drop the test. 
Now TOEFL is also getting competition, and the competition has set off debates at American colleges over the best way to measure students' English competency, the obligations of American colleges to students from the poorest parts of the world, and the changing nature of international recruiting.
The challenger to TOEFL is the International English Language Testing System,  known by its acronym, IELTS. Co-sponsored by the English testing entity of the University of Cambridge, and British and Australian organizations that encourage international education, IELTS has long been the dominant test for students from non-English speaking countries seeking to enroll in English-speaking nations of the British Commonwealth. But in the last three years, IELTS has quietly become a force in the United States as well, where the number of colleges accepting IELTS on equal footing with TOEFL has doubled, to more than 800.
The increased acceptance of IELTS in the United States has in turn made the test more popular for students abroad. The Chinese press -- which pays close attention to trends in international education -- has had numerous reports about IELTS. People's Daily  reported that in the last three months, 17,000 people took the IELTS in Shanghai, up from 10,000 in the same three-month period a year ago, and that IELTS officials have been adding testing locations and exam times all over China.
The competition already appears to be prompting changes by both testing agencies -- with IELTS moving toward more Internet-based testing (a change recently instituted by TOEFL). And TOEFL last month for the first time adopted a sliding scale on fees, so that people taking its test in Bangladesh don't have to pay the same as those in Switzerland. (IELTS has long had such a policy, and some American college officials have been bothered by TOEFL's old policy, fearing it discouraged applications from the third world.)
"These two are really going head to head, and that's going to benefit the consumer," said Julia Funaki, associate director of international education services at the American Association of Collegiate Registrars and Admissions Officers.
While partisans of the two tests point to their differences, they actually have a lot in common. Both are "four skills" exams (reading, writing, listening, speaking). Both are offered all over the world. In terms of language, IELTS tests "international English," and passages in the test are intentionally a mix of styles of what might be used at universities in Australia, Britain, Canada and the United States.
The most notable difference in the tests may be the way speaking is judged. IELTS uses a live, face-to-face interview with the test taker, while ETS has students taking the TOEFL speak into a microphone for analysis by a panel of test reviewers later.
"Live, face-to-face speaking is more authentic," said Beryl Meiron, executive director of IELTS International, the United States branch of the organization. She noted that examiners must undergo extensive training and that years of using the system have enabled the organization to be certain that grading is appropriately rigorous.
"You really need to be able to manipulate the language well to do well on our test," Meiron said.
That interview is the top advantage of IELTS over TOEFL, said Andrea Scott, director of graduate admissions and recruiting for the University of Minnesota-Twin Cities. TOEFL "is not interactive. You are having a conversation with a computer. In IELTS, the person is trained to gauge the student's ability, and to increase or decrease the difficulty of the conversation to tell more," Scott said.
While Minnesota accepts both TOEFL and IELTS and still (like most American institutions) gets far more TOEFL scores, Scott said she would like to see more applicants use IELTS.
Others cite the speaking test as an advantage for TOEFL. Carol Lynch, the former graduate dean at the University of Colorado at Boulder and now a senior scholar at the Council of Graduate Schools, said that she followed the development of the TOEFL speaking test as an advisory board member for that test. She said the TOEFL speaking test is more comprehensive and consistent, which is vital for a speaking test to be reliable. The speaking test is a new addition to TOEFL, and Lynch called it a "wonderful addition," designed very specifically to meet the demands of college admissions officers.
Mari Pearlman, senior vice president of the higher education division at ETS, said that having six people review speaking selections was far superior to the IELTS approach. "We're not comfortable with a single oral proficiency interviewer," she said. "In a large scale, high stakes assessment, you shouldn't have the variables of any human-to-human interaction," she said.
Privately, some ETS partisans go further, and allege that IELTS examiners may be friends or teachers of test takers and have a bias in favor of helping them. Meiron said that was "completely untrue," and noted explicit rules about conflict of interest. All IELTS testing centers have multiple trained examiners, she said, so that if an examiner realizes he or she has a conflict, someone else is available to step in.
Cost comparisons are not as easy to make as one would think. Both testing entities claim that their test is less expensive, and Pearlman of ETS said that last year, before TOEFL went to differential testing, it was still less expensive on average than IELTS. The issue is important because a price difference of $20 -- which might seem like small change in the context of college costs in the United States -- is a huge sum to a student in a developing nation trying to figure out if she will be able to gain admission to an American college.
IELTS posts its prices in local currency while TOEFL prices are posted in U.S. dollars. Converting IELTS fees to TOEFL prices in developing nations finds many where prices are within $10, but where IELTS had an edge until TOELF introduced differential pricing. In many developing nations, TOEFL currently costs $140 -- which is less than the IELTS fees in Kenya ($153) or South Africa ($183), but more than IELTS in Bangladesh ($115).
Robert Watkins, assistant director of admissions for graduate and international admissions at the University of Texas at Austin, said that there has been a "perception issue" on TOEFL's cost because it did not have differential pricing. Watkins is a member of TOEFL's advisory board and believes his university probably receives more TOEFL score reports than any other institution. He thinks TOEFL is a "slightly better" test, but Texas started accepting IELTS scores two years ago -- after the university conducted extensive tests on IELTS. "We think it's a good test," he said.
Watkins and others said that a big part of the context for the growing IELTS interest is the changing nature of competition for international students. Post-9/11, many American universities struggled to maintain their international enrollment levels as visa regulations became more strict at the same time that many other countries' universities -- some of them in IELTS strongholds -- started to step up recruitment of the best foreign talent.
Suddenly, the Chinese or Indian applicant wasn't just weighing MIT and Texas and Stanford (and sending the same TOEFL score to all of them), but also Cambridge and Monash, for which he or she was taking IELTS.
Brown University is this year, for the first time, saying that IELTS scores will be considered the same as TOEFL for undergraduate applicants from other countries. Panetha Ott, director of international undergraduate admissions, said she views this as "a question about access."
Many international applicants apply to Brown and Australian universities, where IELTS is the norm. "It makes sense that they should be able to take one test instead of two."
And then there is the question of coaching -- or, some would say, cheating. Many countries that send many students to the United States -- China in particular -- have huge coaching industries. Some are legitimate tutoring services or programs equivalent to those offered for the SAT in the United States, where students take practice tests and learn basic strategy. Other such services in China -- hugely popular with students -- teach students various less-than-educational ways to inflate their scores beyond their actual skill levels.
TOEFL is using a new, Internet-based test this year and "the word on the street is that the schools don't know how to beat the new test," said Watkins. He noted that there was a huge spike in China of students taking the last versions of the old TOEFL test and that some of the spike in IELTS followed the introduction of the new TOEFL.
This rationale for IELTS interest plays both ways, of course. It suggests that some of those flocking to IELTS are not doing so for the educational value of the one-on-one speaking test. But it also suggests that the TOEFL of previous years may have been more coachable than officials then admitted.
Pearlman of ETS said that she would have been surprised if IELTS tests weren't going up now. Students around the world "create mythologies about tests," so changes result in "intense avoidance behavior." Pearlman said that the new TOEFL isn't just new, but has been designed "to make coaching difficult," but many others expect the private schools in China to soon be boasting of their ability to boost TOEFL scores (and IELTS scores too).
The acronyms IELTS and TOEFL can be found all over blogs that are otherwise in Chinese, and new mythologies may soon be spread. "The students really care about these test, and they talk about them a lot," said Watkins.