I am a high school English teacher. I currently teach six sections of 30-35 students. I already spend my nights and weekends lesson planning/assessing writing, and you want to double my student load? Fuck off. I’d quit tomorrow.
The grading (and lesson planning/assignment & test writing, though those scale anyway) would be split between the teacher giving the lesson and the one acting as a surrogate, so they'd basically still have the same load each.
Edit: probably on an alternating assignments basis rather than a "half the students' papers for you, half for me" basis, for grading consistency/fairness reasons
Edit2: Actually, for feedback-latency reasons it's probably better to split grading the other way. I wonder whether it's better to split each assignment randomly, or grade as two separate classes with shared lectures.
For tests and exams it’s common for teaching assistants to mark the same few questions on every test, usually on the same page. It helps catch cheating and plagiarism and keeps grading consistent.
When I was a TA we’d split the stack of paper tests evenly and rotate them every few days to grade them in parallel. It’s even easier to do the splitting if tests are submitted online.
Oh, yeah! My profs'd also post the list of which TA did each (sub-)question, so that if we had questions about why we lost marks we knew who direct them to (although all grading disputes had to go to the prof, to disincentivise people from arguing with the TAs)
And with two teachers, you'd also be able to have each write half the questions, and split the grading that way.
