For a unit divided into three sections, which end-of-unit test design would have the highest validity?

The design of an end-of-unit test with one long essay question that synthesizes content from all sections has the highest validity because it assesses not only the students' understanding of individual sections but also their ability to integrate and apply knowledge across the entire unit.

This format encourages students to demonstrate their critical thinking and analytical skills by connecting themes, concepts, and details from the different sections, which reflects a deeper level of understanding. Writing an essay requires students to articulate their thoughts clearly and coherently, providing a comprehensive assessment of their knowledge and ability to synthesize information.

In contrast, other options, while useful in their own right, may not effectively measure the holistic understanding of the unit. For instance, multiple-choice questions tend to focus on recall of specific facts rather than synthesis of information. Short answer questions might limit responses to isolated details from each section, and a group presentation, while collaborative, may not individually assess each student's grasp of the content. All these alternatives could miss the opportunity to evaluate a student's comprehensive ability to connect concepts across the unit, which is why the essay question stands out in terms of validity.