Which two characteristics are critical for a well-designed test?

Validity and reliability are fundamental characteristics of a well-designed test, particularly in the context of educational assessments.

Validity refers to the extent to which a test measures what it is intended to measure. For instance, in a fire instructor certification test, validity ensures that the questions accurately assess a candidate's knowledge and teaching skills relevant to fire instruction. High validity means that the results can be interpreted confidently, reflecting the true competency of the test takers.

Reliability, on the other hand, pertains to the consistency of the test results over time and across different populations. A reliable test yields the same outcomes upon repeated administrations under similar conditions. This characteristic is crucial for ensuring that the assessment is fair and that it can be depended upon to evaluate candidates without significant variability unrelated to their actual abilities.

Together, validity and reliability ensure that a test is both meaningful and trustworthy, making them indispensable in the design of assessments in educational and professional settings. Other characteristics such as complexity, length, knowledge, and application, while relevant in context, do not directly address the foundational integrity of the assessment as validity and reliability do.