Which factor is essential for achieving reliability in an assessment?

Achieving reliability in an assessment hinges on the consistent application of grading policies across all tests. Uniform grading policies ensure that the criteria for evaluation are clearly defined and applied consistently, which minimizes subjective discrepancies among different evaluators or grading occasions. When all tests are assessed under the same guidelines, it increases the likelihood that results will be replicable and trustworthy, highlighting that the assessment is measuring what it intends to measure.

In contrast, variety in grading methods, variability in question types, and frequent changes in test administration all introduce inconsistencies that can undermine reliability. Different grading methods can lead to varying interpretations of student performance, while variability in question types might not allow for a stable assessment of the same skills or knowledge, making it difficult to compare results. Frequent changes in how tests are administered can create discrepancies in conditions that affect student performance, further clouding the reliability of the results.