A Simple Model to Determine the Efficient Duration of Exams

Area of Science:

• Educational Measurement
• Psychometrics
• Quantitative Psychology

Background:

• Exam duration is a critical factor influencing student costs and assessment validity.
• Traditional models often overlook the interplay between measurement error costs and direct measurement costs.
• Understanding these costs is essential for optimizing educational assessment design.

Purpose of the Study:

• To develop a theoretical model quantifying the costs associated with exam duration.
• To identify the optimal exam duration that minimizes total student costs.
• To explore the implications of this model on assessment reliability and course design.

Main Methods:

• Utilized a classical test theory model, incorporating assumptions about the assessment context.
• Expressed exam costs as a function of duration, measurement error, and measurement costs.
• Applied the model to a practical example with a given reliability coefficient.

Main Results:

• Demonstrated that total exam costs can be minimized by adjusting exam duration.
• In an example with reliability .80, the optimal duration resulted in a shorter exam with reliability .675.
• Optimal exam duration is influenced by factors such as course study load.

Conclusions:

• The theoretical model provides a framework for optimizing exam duration based on cost-benefit analysis.
• Findings suggest that shorter, more focused exams may be more cost-effective for students.
• Further empirical research on student preparation time for resits is recommended to refine these models.