Which type of assessment provides detailed feedback on specific skills and competencies?

The correct answer focuses on the nature of diagnostic assessment, which is specifically designed to evaluate the strengths and weaknesses of students in detail. This assessment aims to identify individual skill levels and competencies before instruction begins, which enables educators to tailor their teaching strategies to better support each student's learning needs. Diagnostic assessments often include various forms of testing or evaluation that pinpoint specific areas where a student may require additional support or enrichment.

In contrast, formative assessment is primarily used during the learning process to monitor student progress and inform instructional adjustments. It provides ongoing feedback but may not be as comprehensive in detailing individual skill acquisition compared to diagnostic assessments.

Summative assessment generally occurs at the end of an instructional period, measuring overall learning outcomes rather than specific competencies. Although it provides an overview of knowledge gained, it lacks the personalized feedback characteristic of diagnostic assessments.

Norm-referenced assessment compares a student's performance against a larger group. This type of assessment is useful for understanding relative performance but does not focus on individual skill competencies in a personalized manner, unlike diagnostic assessments that are geared towards identifying specific learning gaps.

Thus, the unique emphasis of diagnostic assessments on detailed and specific skill evaluation makes it the best choice for providing the feedback needed for targeted educational improvement.