As useful as they are, GEs have a number of drawbacks. One is that the rate of growth in a subject area is not constant as children get older. For example, the typical child gains reading skills faster in the primary grades than later on. Therefore, a gain of one GE denotes greater growth in the early grades than in later grades. If you want to know, for example, whether the rate at which students learn math slows down or speeds up when they move to middle school, GEs by their very nature cannot tell you. The average student will gain one GE per year regardless.
