Students are calling for greater transparency from the International Baccalaureate over its "dual" approach to grading this year.
Anger is growing among those who feel that the IB's decision that some candidates will sit exams in 2021 while others will have grades decided through teacher assessment is unfair.
They are demanding more clarity over exactly how the grading process will work.
International Baccalaureate 2021: UK exams cancelled
International Baccalaureate: Why UK exams are unlikely
IB 2021: Exam safety questions
The IB said earlier this month that it would offer a dual route for its grading processes this year, with schools in some countries holding exams, while other students will be awarded allocated grades through teacher assessment.
Students have called for more clarity and openness about exactly how historical data will be used to produce allocated grades under the non-exam route.
International Baccalaureate: Students worried about results being fair
They are worried that the system will put an artificial limit on the achievements of students who might have improved on their school’s historical record if they had the chance to take exams.
"Why would it be fair to be assessed based on historical data? Do former students matter to what your grade could be? IB should make the grade calculation method public to the world and show us that it is fair," Mio, a student living in Italy, told Tes.
Students said the lack of clarity from the IB was affecting their wellbeing, and that the fairest approach might be for students to decide whether or not they should take exams individually.
The International Baccalaureate is also being criticised for its failure to publish a worldwide breakdown of which provinces or countries will be able to hold exams under its "dual" approach.
"I think that by making it transparent which countries will take the exams and which will not, the students will have clarity on which countries are taking the exams," one student told Tes.
They added that they were concerned that students in countries that had experienced lower levels of lockdown would push global grade boundaries up.
"Another thing is that we really do not know how the IB will grade us since the dual route is now a thing – will the students taking the non-exam route be graded differently for their IAs [internal assessments]? Will the criteria be the same?" they said.
"The whole situation is very unclear and I believe that not knowing which countries are taking the exams is only adding into the disorganisation."
A spokesperson for the IB said: "During the May 2021 series, we will look for evidence in regions and countries of an unusual impact of the pandemic and, if needed, apply measures to mitigate it.
“All IAs, for both exam and non-exam routes, will be graded in the same way with the same criteria.
“We are working with schools to help them assign accurate predicted grades. As such, we will provide them with a generous distribution of grades for their school to act as a guide in this process. If teachers do not believe this distribution reflects their students’ abilities, we will work with them to see if it needs to be adapted.
“We have a dedicated team based around the world who are holding near-continuous conversations with our schools, associations and ministries as we navigate this session together.
"Our schools receive regular updates and information, currently every week. We encourage schools to continue this conversation with their school communities and have developed resources for them to use for that purpose.
"The IB prides itself on its relationship with its schools. We wanted schools and students to find out from us direct, not from a country-by-country general release, whether they are taking the exam or non-exam route.
"As schools will appreciate, this is a fluid picture, with the pandemic affecting different areas in different ways at different times, and, as such, the global map of the May 2021 plans is likely to change right up until the exams are sat.”
On whether students could decide individually about if they should take exams, the spokesperson said: "Unfortunately, this is not possible due to scale of the challenge it would present, both in terms of administering such a process and guaranteeing fairness between students.”