The Importance of Validity and Reliability in Assessment

When designing an exam, the first step is often overlooked: ensuring its validity and reliability. According to a case study published in The Journal of Competency-Based Education, following best-practice design principles can help preserve exam validity by avoiding inadvertent errors that can have a devastating effect on the assessment's overall accuracy.

A valid assessment measures what it was designed to measure, as noted by the University of Northern Iowa Office of Academic Assessment. However, this is only possible if test designers and instructors consider all aspects of assessment creation, beyond just content. Failure to do so can compromise the validity of an exam.

One way to ensure an assessment's validity is by measuring its reliability. Reliability refers to how accurately or consistently an assessment measures what it was designed to measure. There are three types of reliability measures that can be used: internal consistency, alternate form, and test-retest.

Internal Consistency Reliability measures how well the actual content of an assessment works together to evaluate understanding of a concept. This type of reliability is essential for ensuring that students who answer multiple questions on the same topic will give consistent answers.

Alternate Form Reliability measures how test scores compare across two similar assessments given in a short time frame. This type of reliability is important for ensuring that students who take different versions of the same test will produce similar results.

Test-Retest Reliability measures the replicability of results, or whether students who take the same test twice will have similar results each time. This type of reliability is crucial for ensuring that assessments are consistent and accurate over time.

In addition to these three types of reliability, there are other factors that can affect an assessment's validity. For example, deviations from data patterns and anomalous results or responses could be a sign that specific items on the exam are misleading or unreliable.

To ensure that an assessment is reliable and valid, it must exhibit consistent results. Exam designers should use every available resource, including data analysis and psychometrics, to ensure the validity of their assessment outcomes. Poorly written assessments can even be detrimental to the overall success of a program, while invalid or unreliable methods of assessment can reduce the chances of reaching predetermined academic or curricular goals.

By understanding the importance of validity and reliability in assessment, educators can create exams that accurately measure student learning and achievement, ultimately leading to better outcomes for students.

Importance of validity and reliability in assessment