I've often joked that teachers need secretaries, but in truth that's not actually what I need at all. I need to do that grading and commenting and data-entry because that's what tells me how my students are doing.
What I need is smaller classes. If all of my students complete their work, I finish my day with anywhere between 70 and 95 papers to look at a night. If I spend 2 minutes reading and assessing per paper on the 70-paper day, that's 140 minutes, or just over two hours I'm spending grading. Add another 30 seconds per paper for the data entry and that's still 35 minutes of entering grades, for a grand total of five minutes shy of three hours of work. On days where I see three classes instead of two, those numbers are obviously higher.
Though a first glance at my schedule might indicate that there is time in my day for this work, here's the reality:
A Day
8:15-9:45 - prep period, grade and enter two assignments, get ready for first class
9:52-11:22 - teach first class
11:29-12:14 - lunch
12:14-1:44 - teach second class
1:51-3:21 - alternately a prep period for grading or a meeting
B Day
8:15-9:45 - teach first class
9:52-11:22 - teach second class
11:29-12:59 - teach third class
12:59-1:44 - lunch
1:51-3:21 - Academic Lab with students or a meeting
Over a two-day period, I only have a total of, at most, 180 minutes that I'm not teaching, and every other A day I'm in a meeting instead. I don't count my lunch; it's time I don't get paid for. You may be thinking, "Okay, you're working six-and-a-half hours. What are you complaining about?" Good point. Let's add in that paper-grading I can't get done during the day, about 90 minutes on average. That gets my work day to the standard eight-and-a-half hours.
And now, I need to make my teaching materials for tomorrow (30 minutes), tweak my lesson or unit plans (15), tweak my curriculum maps (10), design the assessment my students are taking next (20), re-read a chapter of the book I'm teaching (20), write a letter of recommendation (30), talk to a colleague about a field trip we're planning (10), send and reply to emails (15), call parents of kids who are struggling (30), and clean my classroom (20). So that's another three hours. Smaller classes can't reduce these extra tasks; I'll be doing planning and sending emails no matter how many students are in front of me in a day, but I can reduce the amount of time I spend assessing papers if there are fewer papers to assess. No wonder teachers are so fond of group projects.