Another very old principle of good teaching is "do not
go to the next topic without being sure that students are
familiar with all prerequisites." Strictly speaking this
principle can not be used except in private tutoring or
in very very small classes. In large classes it means
"do not allow students to pass a course unless reasonable
expectations are satisfied." I was never asked to follow
this principle by an administrator. But I was often asked
(indirectly) to do the opposite: something like "education
is not for an elite, give everybody a a chance to succeed."
Suppose a group of three teachers (math, physics and
shop) are assigned a task of teaching three to five
motivated college students for two years.
Ludwik Kowalski