The word 'dissertation' can mean a lot of things. Some people are talking about 8000, which seems more like an assignment, frankly. I could probably crank out 8000 words in 3 weeks and make a reasonable job of it, so long as it was on a subject that I already knew something about.
Guide to Planning your dissertation.. Conclusion (800 to 1,000 words) Proofreading involves checking the content and appearance of your written work: looking for errors in typing, spelling and grammar, and ensuring that it is presented in a style that meets the requirements of a module or course. Proofreading is a skill that requires time.