Coordination of a class taught by different professors: how to be fair to the students? A typical freshman course on calculus has about 100 students every semester. If the course is divided into 4 sections, each has 25 students and a different instructor.

Because the instructors are different, a student's grade may strongly depend on who teaches his section. Lazy students could ask other students before registering who is the easiest grader or who makes easy or straightforward exams, etc. This is unfair to the rest of the students.  

Has anybody else faced the same problem? And how did you overcome it? 

What criteria one should impose to guarantee that a student's grade will only weakly depend on who is teaching him?. 

We are thinking about giving all sections the same midterms and finals. But, obviously this is not enough
The more common problem across multiple sections of large courses taught by several different instructors is content drift, not grade drift. At my institution we have three General Chemistry I sections, and the distributions of A's, B's, and C's among the students does not change significantly depending on which of 6 people teach the course. The distribution of D's and F's does vary, however. What is more troublesome to us is that some instructors will cover 8 chapters, some will cover 9, some 10, and so on.

However, if you really want to minimize grade drift, then do the following, which will also eliminate content drift:


Coordinate the class - same textbook, same syllabus, identical assignments, exams, everything.
Agree ahead of time on a common grading policy, including cutoffs, curves, grade disputes, etc., and enforce it uniformly.
Teach from a common outline so that all sections get the same material in the same week. 
Meet frequently, including at least one meeting before the class starts.
Grade equitably, which may seem difficult, unless you do the following: Professor A grades all of Assignment 1 across all 4 sections. Professor B grades all of assignment 2, etc. Better yet, hire one person (a grad student maybe) to do all of the grading for all 4 sections.