There is a dark secret in education that is seldom acknowledged: There is no perfect system of student assessment. All systems from examinations to internal assessment to norm-referenced to standards-based assessment are inherently flawed.
Until the 1990s New Zealand operated an assessment system in our secondary schools that could be described as norm-referenced. Students mainly sat national exams at schools and were scaled and ranked against each other. This system consigned a large portion of our population as academic failures from as young as 15. Such labels tend to be self-fulfilling and often lifelong.
From the 1990s our schools moved towards a system of standards-based assessment. Students would be assessed against objective standards of knowledge and skills. If they achieved the standard they would pass. It was likened to our system of issuing driver's licences. You either met the standard or you didn't.
This system sounds fair in theory but runs into problems in practice. The problems relate to having objective and clear standards of achievement. Those who are teaching the students, or setting the assessments and marking them, need to be in total agreement about the required standards to be met. This is easier said than done.
In 2002 secondary schools introduced NCEA which is a standards-based model of assessment. It was based on various levels of attainment from "excellence" to "merit" to "achieved" to "not achieved".