nd doctoral degree programs in various universities Knowledge / skills tested: Analytical writing, quantitative reasoning and verbal reasoning. Score / grade validity: 5 years Duration: About 3 hours and 45 minutes (includes 1-minute breaks after each section and a 10-minute break after third section). In addition to the General Test, there are also six GRE Subject Tests testing knowledge in the specific areas of Biology, Chemistry, Literature in English, Mathematics, Physics, and Psychology. The length of each exam is 170 minutes.