<p>I suspect each has its purpose.&nbsp; A 5 question test can be a useful memory retention exercise with recently&nbsp;recently presented content&nbsp;by helping students committ&nbsp;the right information to memory&nbsp;vs content that is not as important.&nbsp; A 20 question test is&nbsp;a better assessment of broader sets of content.&nbsp;&nbsp; But even a 20 question test can be manipulated to be learning tool.&nbsp; By careful attention&nbsp;to a progressive&nbsp;question sequence, a teacher can build a kind of dvidiing line between what a student knows vs what they don't know.&nbsp; Subsequent tests would then be used to see if the student has moved that line.</p>