Which aspect of evaluation is used when a teacher ensures that students complete an exercise in mathematics and also makes sure that the instructions are clear and specific?

Validity means an evaluation actually measures what it is meant to measure, which clear, specific instructions and a genuinely completed task help secure.

Practicality concerns whether a test is easy to administer, score and afford, not what it measures.

Reliability is the consistency of scores across repeated administrations, a different quality.

Consistency is essentially another name for reliability and does not describe measuring the intended trait.

Validity, reliability and objectivity are the three chief characteristics of a good test.

Content validity, one of its types, checks whether the items cover the intended syllabus.