A、The number of people who take the tests. B、Testing methods that the tests adopt. C、Languages that the test papers are based on

Most American colleges and universities accept one or both of the two major tests. One is the Test of English as a Foreign Language, known as the TOEFL. The other is the International English Language Testing System, or IELTS. The TOEFL is given in 180 countries. The competing IELTS is given in 121 countries. One million people each year take the TOEFL. Same with the IELTS, says Beryl Meiron, the executive director of IELTS International. She says 2, 000 colleges and universities in the United States now recognize the IELTS.(17)Schools might accept it only for undergraduate or graduate admission or both. The IELTS is a paper test, while the TOEFL is given on paper only in places where a computer test is not available. The TOEFL paper test costs 150 dollars. It tests reading, listening and writing. A separate Test of Spoken English costs 125 dollars. The computer version is called the TOEFL iBT, or Internet-based test. The price is different in each country, but generally falls between 150 and 200 dollars. The TOEFL iBT and the IELTS both measure all four language skills— listening, reading, writing and speaking.(18)But with the IELTS, the speaking test is done separately as a live interview.
    You speak with an examiner who is certified in ESOL—English for speakers of other languages. IELTS International says the test measures true-to-life ability to communicate in English for education, immigration and employment.