Mid term is subjectively the point at which one can evaluate and prognosticate how students are doing and will do at the end of the course. This evaluation has many elements, several of these are related to information coming from precious courses more so when students in the present course are known to the professor from previous courses. One of this elements is the stage or level of knowledge the student had previous to this course another (and most important) is the change in attitude that the student has had during previous courses and now can be compared to the changes in attitude during the present course.
There are other external factors to consider that are more difficult to change, going from cultural values in the education previously obtained by the student to the variety of skills necessary for that particular discipline, such as mathematics in the case of science. One aspect one is finding hard to deal with is the disconnect between the rational interpretation necessary of problem solving and the emotional connection with the rationality of the individual. It is a roadblock when the professor asks the student: can you see this? can you feel if it? does it makes sense? and the students with the problem and answer in front of her/him is unable to feel the rightness of wrongness of the answer.
It is not that the student is not engaged, of course is even worse when is not engaged and not much can be done except to help the student get engaged.
As the student doesn't "feel" the connection between answer and problem when developing skills s/he moves away from being engaged, then keeping attention to the class becomes impossible and if the teacher doesn't stop and makes a personal appeal to the student to continue being engaged that student will be lost for the rest of the class and maybe the rest of the course. Teacher have to develop techniques (eye contact, moving around in the room, etc) so s/he can keep an individual connection with each student in the class. Of course this one-on-one participation will at the end be determined by the student! So the question is: Can students be forced to engage? and if so: How?