In a series of studies, Sommer found that almost all students (even successful ones) reported at least some cramming for exams, that most students reported cramming more in college than in high school, and that most students did not begin serious study for final exams until the week before finals began.
Thus one of the conditions for flow (that the task is engrossing, enjoyable, and engaging) may be absent when students engage in cramming for an exam or written assignment.
At the same time, test and flow scores were more strongly related to cramming for the necessity-crammers than the choice-crammers.
When cramming for an exam, the challenge is to incorporate a large amount of material in an efficient manner.