tweet it) I had a green highlighter for correct work and a pink highlighter for incorrect work.
Believe it or not I stuck with it the whole year!
The routine I ended up using:
If the whole problem was correct I either highlighted the answer (if it was short) or the question number (if it was a longer response) in green. I sometimes highlighted key words in green to draw attention to the vocabulary/reasoning I was looking for. If the whole problem was blank I highlighted the question number in pink. Otherwise I highlighted the first mistake pink.
Pro: It was easy for kids to see exactly what needed fixing. They copied down the line above the pink, fixed the pink part and then continued from there.
Con: I had one student who was red/green colorblind. She asked her friends to tell her which was which until mid-year when she told me she was colorblind and I went back over hers with pen after that. Next year I will have to ask up front if anyone is colorblind.
Pro: I wrote less. All those helpful notes seem like such a good idea, but they take up a lot of time and the students didn't have to do the thinking to figure out their mistake. Kids can always ask a neighbor who got it right or ask me if they can't figure out their mistake. I did occasionally write something with either a nearby pen or the highlighter since I got thin ones.
Con: I bought a lot of highlighters and only used the pink and green ones. I didn't need a lot, none of them have run out, but I wanted a set in my desk at school, a set in my grading bag and a set at home.
Pro: The kids like it. A student made up a test after school and asked me to grade it. I grabbed whatever pen was in front of me and he said, "No! You have to use the highlighters!"