Standardized test scores are very significant in determining admission to professional schools (the LSAT for law, MCAT for medicine, GMAT for business). In the wake of court rulings, many medical, law, and veterinary schools simply plug the relevant test score into a formula and it is weighted heavily--a good score will not guarantee admission but a poor one may seriously harm your chances.
For admission to most Ph.D. programs, the GRE is not as overwhelmingly decisive, and other factors such as grades, research experiences and letters of recommendation are more important. However, the GRE may be significant in determining who is offered the most generous internal funding for Ph.D. programs at some universities. In an era of grade inflation on many campuses (even if not at WPI), some graduate schools rely on the GRE or other test scores when they compare students from different schools or disciplines in deciding on offers of admission or merit-based financial aid.
Students should engage in some formal test preparation using books, study groups, or commercial test-preparation services. Preparing with other students in small groups is usually a more effective strategy than studying alone. Given the weight that these scores are sometimes given, the time and effort put into test preparation is certainly worth the investment.
- What You Need to Know About Entrance Exams from Graduating Engineer and Computer Careers Online.