School-based assessment (SBA), meaning coursework, projects, portfolios, practicals and continuous teacher assessment that count towards a final grade, has become a fixture of education systems worldwide. Supporters see it as a fairer, richer picture of what students can do than a single high-stakes exam. Critics worry that it is less reliable, more burdensome and, crucially, less equitable. Both sides have a point, and the balance between them matters for every learner.

The strongest argument for SBA is authenticity. Exams test what a student can recall and write in two or three hours; SBA can capture skills a timed paper cannot, such as research, oral communication, teamwork, practical competence and the ability to improve work over time. In vocational and creative subjects especially, a portfolio or practical task often says more about competence than any written answer.

SBA also spreads the stakes. When a grade rests on one exam, a bad day, illness or anxiety can undo two years of work. Continuous assessment gives students several opportunities to show what they know, and reduces the pressure that high-stakes testing is widely linked to.

SBA can strengthen learning itself, too. Since assessment happens during the course, teachers can give feedback that students act on, and students learn to plan, self-assess and manage longer tasks. End-of-course exams rarely offer this formative dimension.

Finally, SBA draws on teachers' professional knowledge. Teachers see students over months, not hours, and can judge progress, effort and understanding in context. Trusting that judgement can also raise the standing of the profession.

Yet the same features that make SBA attractive also create problems. The main criticism is reliability. Teachers mark their own students, often interpreting criteria differently, and moderation is costly and imperfect. A grade earned in one school may not mean the same as an identical grade in another, which undermines comparability for universities and employers.

Authenticity of the work is another serious concern. Tasks completed at home are hard to verify. Tutors, parents, online services and, increasingly, generative AI can all shape what is submitted, making it difficult to know whose work is being assessed. Worries of this kind contributed to England's decision to scale back coursework in its GCSE and A-level reforms of the 2010s.

SBA also creates workload pressures. Students facing simultaneous deadlines across several subjects can experience assessment overload, trading one exam crunch for a constant one. Teachers take on heavy marking, record-keeping and moderation duties, and may feel pressure from parents or school leaders to inflate grades.

The most serious objection is that SBA can widen the very gaps it is often meant to close. Working-class students are disadvantaged in several connected ways, some obvious, others far more subtle. A lot of SBA opportunities happen outside the classroom, and home circumstances vary enormously. Middle-class students are more likely to have a quiet place to study, a reliable computer and internet connection, books, and parents with the time, education and confidence to advise on a project. Working-class students may share crowded spaces, carry caring responsibilities or part-time jobs, and have no one at home familiar with what assessors expect.

Money matters a great deal too. Families who can afford private tuition can buy extra help with coursework, sometimes to the point where the line between support and authorship blurs. Projects requiring materials, travel or equipment favour those who can pay.

Cultural capital plays a quieter role. Tasks that reward particular styles of writing, presentation or confident oral performance may favour students whose home language and experiences match the school's expectations. Teacher judgement, however professional, can also be swayed by unconscious bias linked to accent, behaviour or perceived background.

Research on teacher-assessed and predicted grades has found patterns that tend to favour more advantaged students, though findings vary by context. Exams are not neutral either, since wealthier families also pay for exam coaching. But the controlled conditions of an exam hall at least place every candidate under the same rules on the day.

On balance, SBA is neither a cure-all nor a mistake. Its benefits are real, but so are the risks to reliability and equity. The fairest systems tend to blend methods: carrying out key tasks under supervision during school time, providing resources and study spaces for students who lack them, using clear criteria with robust external moderation, and limiting how many tasks fall due at once. Schools can also run structured after-school coursework clubs, so that help is not left to what families can provide. Designed this way, school-based assessment can recognise a wider range of talents without quietly rewarding the advantages students bring from home.

Dr De Giovanni is a Chartered Occupational Psychologist