What is a potential drawback of relying solely on diagnostic tests?

Relying solely on diagnostic tests can indeed present the drawback of not covering all subject areas comprehensively. While diagnostic tests are beneficial for assessing specific skills and knowledge areas at a particular point in time, they often focus on a limited range of topics or skills. This narrow focus means that students may not be evaluated on all relevant aspects of a subject, potentially leaving gaps in understanding or overlooking broader competencies that are essential for mastery of the material.

In contrast, other forms of assessments—such as formative assessments, summative assessments, portfolios, and projects—can provide a more rounded evaluation of a student's abilities and understanding. This comprehensive approach helps in identifying diverse strengths and weaknesses beyond what a single diagnostic test might reveal. Therefore, relying exclusively on diagnostic tests can lead to an incomplete picture of a learner's overall academic progress and needs.