What describes an exam administered without covering all content in a class?

A lack of content coverage in an exam directly impacts its validity. Validity refers to the extent to which an assessment measures what it is intended to measure. If an exam does not cover all the relevant material taught in the class, it cannot accurately assess students' knowledge and understanding of that material. For instance, if essential topics are omitted from the exam, students may perform poorly not because they lack understanding, but because those topics were not assessed.

In contrast, reliability refers to the consistency of the test results across different occasions or forms; credibility pertains to the trustworthiness of the assessment as interpreted by stakeholders; and subjectivity deals with the personal judgment of the scorer. While these factors are also important in considering the quality and effectiveness of an exam, they do not specifically address the issue of content coverage, making validity the most appropriate descriptor in this context.