I agree with Christiana about reading being different from searching. During my thesis writing I even allocated different moments during workdays for these activities.

Each of us has a different method for writing, I guess. My method includes a lot of re-writing. Being a non-native English speaker, I start off writing rapidly (often in a combination of Dutch and English) and then go through endless cycles of grammar and spell-checking and refining each and every sentence.
So, I would add another column: re-writing.