The General Education Development (GED) test is designed to prove a person has attained the knowledge and test-taking skills equivalent to an American or Canadian high-school graduate. The test was created by the American Council on Education (ACE,) which also scores the test and develops a scoring standard that is optional for municipalities to follow. ACE also calculates trends in the pass and fail rate that can be used by municipalities, colleges and other academic institutions, the military and employers to help gauge what they consider good GED scores.
Although ACE scores the GED exams, it is the municipality where a test is taken that interprets the scores for awarding diplomas such as a "Certificate of General Educational Development" or similarly titled credential. Each municipality can lawfully create its own standards for scoring and designating pass or fail, but most follow ACE's recommendations and set similar standards.
Most states do not score directly based on the percentage or amount of correctly answered questions when interpreting GED scores. (In the case of the writing exam, this would be impossible as it consists of one essay scored by two graders that must give a grade within one point of the other.) Instead, they use ACE's five-test battery scale to average a person's scores in the five areas of math, sciences, social studies, writing and reading comprehension. Typically, scores are added together and divided by the number of tests completed.
The standard scoring range is from a minimum of 200 to a maximum 800 per subject examination. Most areas pass those with a 410 minimum score for each test, which means that the total of the test scores is 2250 divided by five, for a minimum passing five-test battery score of 450. This makes it common practice for GED takers to have to retake tests where they earned less than 410 to boost their GED scores. These numbers are current in February 2011 and subject to change because ACE gets these figures from sampling GED tests against a random collection of traditional high-school seniors that take the GED. ACE figured this current number from averaging scores of this sample traditional student group so that the GED pass line is meant to indicate knowledge equivalent or exceeding 60 percent of traditional students.
GDE scores can be evaluated by conversion to the Grade Point Average (GPA) scale, most frequently of interest to academic institutions where the test taker is applying. An average score of 701 to 800 is the equivalent of a 3.8 to 4.0 GPA; GED 601 to 700 is a GPA of 3.5 to 3.7; a 501 to 600 is a 3.0 to 3.4; a 401-500 can be converted to 2.0 to 2.9; a 300 to 400 is a 1.5 to 1.9 and 300 or bellow on the GED average is considered the equivalent of a 0 to 1.0 GPA.