The Equality Act Review concluded the teacher assessment system - in place of cancelled exams - could negatively impact black, Asian and minority ethnic (BAME) pupils and those from more disadvantaged backgrounds.
The report authors say predicted grades risk possible "bias by teachers" and do not consider the "material disadvantages" of pupils from poorer backgrounds.
It found nearly 80% of students and parents who responded said they were worried about the predicted grades system.
Report authors say that equates to approximately 4.28 million students concerned about the predicted grades system.
Respondents raised concerns about bias in the classroom in relation to BAME identity, Islamophobia, favouritism, bad behaviour and social class.
The author and founder of the Equality Act Review, said, “As a working class, state educated, first generation to go to university, I would never have gone on to study at Oxford and Yale if my grades were predicted.Stories like mine are common and under pandemic conditions are likely to worsen.”
The report identified socioeconomic concerns as a significant concern in the predictive grades system too.
Of those surveyed, 19% said their schools were predicting grades using past exam performance at the school.
The report warned this is "unfair to students from schools in less advantaged areas" as well as those from poorer backgrounds.
Afzal Khan MP, said: “As the MP for Manchester Gorton, which has one of the highest child poverty rates in the UK, I know full well the importance of opportunity for young people. The existing BAME attainment gap is more likely to have been exacerbated by this pandemic. Bias and other factors mean that predicted grades are not always a true reflection of a student’s potential. These concerns need to be looked at and addressed.
“This much needed report highlights factors which are currently not accounted for in the grades prediction system.
Given the time sensitivity, it is vital that the Government take these recommendations on board ahead of GCSE and A- Level results.”
A spokesperson for Ofqual, the examinations regulator, said:
“The exceptional arrangements in place this summer are the fairest way of giving as many students as possible the opportunity to move on in their lives, despite the cancellation of exams.
“We have asked schools and colleges to provide holistic, evidence-based judgements of the grade they believe a student would have achieved if exams had gone ahead as planned.
“We recognise, and take seriously, concerns about the potential for unconscious bias to inadvertently affect centre assessment grades and rank orders of students and considered these carefully when developing the arrangements – providing additional guidance on objectivity in grading and developing a standardisation model where further safeguards will be introduced. These measures will help ensure, so far as possible, that students are not advantaged or disadvantaged on the basis of their socio-economic background or particular protected characteristics.
“Any student who does not feel their calculated grade reflects their performance will also have the opportunity to sit an exam in the autumn and our consultation arrangements for an autumn series closed last week (8 June).
We expect to publish final decisions before the end of the summer term.”
Concerns about predicted grades pre-date the pandemic, in 2016 a University College London study found most A-level predictions by teachers were over predicted in the majority of cases.
It found only 16% of grades were accurately predicted.