For more than 70 years, the General Educational Development test has been a cornerstone of US education, providing a high school-equivalent qualification for those who dropped out or failed to get the grades when they were at school.
The GED, as it is known, consists of questions in five academic areas and is considered to be a key qualification for finding work. But now the test - taken by more than 674,000 Americans in 2012 - is set to undergo the biggest overhaul in its history, with the aim of making it more rigorous and a better indicator of college- and work-readiness.
From January next year, the five testing areas will be cut to four: literacy (previously separate tests in reading and writing), mathematics, science and social studies. The process will be entirely computerised and for the first time candidates will take the tests online. The questions will be more complex, with the emphasis on critical analysis and thinking skills.
While many experts believe it is time for the GED to change, the plans have also been met with strong criticism that they will disadvantage students and prove too expensive.
Credits that students have already achieved will not be transferable, so those who are partway through will have to start again when the new tests are introduced.
Significant efforts are under way in a number of states to push as many students as possible to complete the test by December, so they do not lose everything they have gained so far.
The scramble to finish is also being driven by the cost of the revamp. Candidates currently pay anything up to $400 (pound;258) to sit the test, but this will triple in some states from next year.
"Most of the folks doing a GED are not well employed or not employed at all, therefore the increased cost is a concern," Henry Merrill, emeritus associate professor of adult education at Indiana University, told TES. "I suspect there will be a short-term impact on the number of people choosing not to take the test as a result.
"Having the tests totally on computers is another concern. Most testing centres have computers, but many older people who sit the test are not comfortable with using them."
Professor Merrill said that dozens of states are now looking into alternative tests from other national providers that more closely resemble the existing GED test.
US-based assessment expert Professor Dylan Wiliam said that part of the thinking behind the reform is to improve the image of the qualification, because its value among employers has decreased in recent years.
"It has always been a kind of catch-up for people who didn't get their high school diploma," he said. "Having it electronically administered and making it more demanding makes sense."
Professor Wiliam, who once worked at a separate assessment organisation, the Educational Testing Service in Princeton, New Jersey, said that the changes will make the GED more worthwhile. "The fact that a person has taken the test shows their commitment and employers can see they are reliable and conscientious," he said.
The GED Testing Service, a joint venture of the American Council on Education and Pearson, said the changes will ensure that the programme is no longer an "end point" but is instead a springboard for more education, training and work.
"Evidence suggests that test-takers who demonstrate fluency with the skills measured in the new assessment will be better prepared for what they plan to do with their lives," a spokesman said. "A graduate will no longer hold just a high school equivalency credential but a road map for life's success."
- 674,051 - Candidates for the US General Educational Development test in 2012
- 581,083 - Number who completed the test (equivalent to 86.2 per cent)
- 401,388 - Number who passed (69.1 per cent)
- 26.5 - Mean age of candidates
- 8.8 - Mean years that candidates had been out of school
- 55% - Proportion of candidates who were male