The Graduate Record Examination (GRE) is a standardized test conducted by Educational Testing Service, ETS, US. The scores of these tests are used as one of the most important parameters by US Universities, colleges while selecting students to their graduate program of study. The GRE General Test aims to assess a student's Analytical writing ability, verbal skills and quantitative skills. As this is a General Test, the test does not relate to any specific field of study.In another way, It simply tests the "mental intelligence" as well as the ability to make decision under time pressure of one.So as it can be taken as an IQ exam whose validity is for five years. After five years, you will need to re-take the test.
The GRE® General Test measures verbal reasoning, quantitative reasoning, and analytical writing skills that have been acquired over a long period of time (not related to any specific field of study).