Students require a lot of practice in order to acquire the instinctive, reflex-like skills that are needed for skillful programming. When workbook-style rote drill is assigned on a take-home basis, the submitted work is often plagiarized. If, however, such work is administered as a quiz, the proctoring diminishes the incidence of plagiarism. Drill-oriented quizzes should have low weight and and low difficulty. Their purpose is to build confidence and reflexes without destroying the skewing the course grade.
Frank Vahid, Chair of CS&E's Committee on Instruction, has offered the opinion that different components of a course may have different instructional goals, some of which are drill:
Grade differentiation makes a lot of sense for some components, less so for others. On a scale from high differentiation to low, the components are: exams, practicals, quizzes, at-home programming, homeworks, in-lab exercises, talks. The former items are intended largely to give grades. The latter are intended to give students practice in a low-stress environment, and therefore we just ``check them off" (which translates to an A). Those lower items don't contribute heavily to the overall course grade, so those As don't make a big difference -- but they serve to encourage the students and to show them that we are not solely focused on grading them, but rather on helping them too. I put talks at end of the list because talks are not an integral part of the catalog description of the courses -- I include those solely to help the students, because I care about them and want them to be successful when they graduate. When we introduce a technical-communication course, those talks will certainly be graded using differentiation (though, even there, I think the first few talks should probably just be checked off).