Assessment should be critical part of the design of course from the very start ; not an add-on .
If students are clear from the start as to how they'll be assessed, they'll focus more on how they're going to use what they learn - especially if the assessment is closely linked to real-life activities!
Assessment criteria “ Design that assessment first. Then design the instruction that leads to that goal.” http://www.learningsolutionsmag.com/articles/739/nuts-and-bolts-the-10-minute-instructional-design-degree “ [authentic assessment] tasks are either replicas of or analogous to the kinds of problems faced by adult citizens and consumers or professionals in the field." http://jfmueller.faculty.noctrl.edu/toolbox/whatisit.htm
Even apparently simple instructions can be misunderstood !
Using a self-test to check understanding of the instructions can build student confidence and highlight misunderstandings early, when they can still easily be rectified .
Simplicity Instructions “ If instructions are clear and guidelines are specific to the learning task, students are more likely to prepare.” http://academics.georgiasouthern.edu/col/id/guiding_learning.php