The Graduate Record Examination or GRE is a standardized test that is an admissions requirement for many graduate schools in the United States. It is created and administered by the Educational Testing Service and is similar in format and content to the SAT.
The GRE? General Test measures verbal reasoning, quantitative reasoning, critical thinking, and analytical writing skills that have been acquired over a long period of time and that are not related to any specific field of study. The GRE? Subject Tests gauge undergraduate achievement in eight specific fields of study.
Unlike the SAT, the GRE is a computer-based test. It is a computer-adaptive test: while the number of questions in any given section is fixed, the difficulty and scoring value of those questions varies according to the previous responses provided by the test-taker. Rather than having a fixed point value, questions of varied difficulty are used in order to 'zero in' on the level of question that represents the upper bound of the test-taker's ability. Because of the way in which the score value changes over the course of the test, early questions are much more important in determining the final score than those that appear near the end of a section. Questions cannot be skipped or returned to.
The General Test consists of three graded sections and one research or experimental section that is not included in the reported score. Multiple-choice response sections are graded on a scale of 200-800, in 10 point increments. The writing section is graded on a scale of 0-6, in half- point increments. Sections may appear in any order on the test, with the exception of the Analytic Writing section, which always appears first.
One graded multiple-choice section is always a verbal section, consisting of analogies, antonyms, and reading comprehension passages. This section primarily tests vocabulary, and average scores in this section are substantially lower than those in the quantitative section.
The quantitative section, the other multiple-choice section, consists of problem solving and quantitative comparison questions that test high-school level math, including algebra and basic geometry. The problems in this section must be solved without a calculator. Average scores on the quantitative section are generally higher than those on the verbal section, though the material may present a challenge for students who have not studied mathematics since high school.
The analytical writing section requires the testee to write two short essays: one presenting their perspective on a statement, and the other analyzing and pointing out flaws in an argument. Each essay is scored by at least two readers on a six-point holistic scale. If the two scores are within one point, the average of the scores is taken. If the two scores differ by more than a point, a third reader examines the response.
In addition to the General Test, there are also eight GRE Subject Tests testing knowledge in the specific areas of Biochemistry, Cell, and Molecular Biology, Biology, Chemistry, Computer Science, Literature in English, Mathematics, Physics, and Psychology. At one point there was also a GRE Engineering exam, but as most engineering graduate schools did not require the exam (many felt it was far too broad) it was discontinued as of April 1st 2001.  Subject tests typically have 70-100 multiple-choice questions that must be answered in 170 minutes. When an applicable subject test exists for an area of study, scores for that particular test are typically given greater weight than those for the General Test. However, the departments at some universities may not require applicants to take their field's subject test. For example, the English test mostly includes questions regarding canonical British and American literature; as English studies has expanded to include more study of female and minority writers, some departments have deemed that the subject test is outdated and not an efficient predicter of graduate success, and therefore do not require it of applicants. In other fields, however, this is not the case, as the tests might represent things that a superlative graduate should know.