I will correct what to me are the outstanding mistakes, but I will not rewrite your essay - then it would be my own, not yours!
It will still have mistakes.
One of the methods to assess students is examination, it often faced with some problems though.
Firstly, examination is arranged at a certain time of an specific day. So all the students cannot have the same conditions due to some accidental problem. Sometimes it was taken in spite of one student having had an awful time before the exam because of sickness, an accident, one of his or her relatives having died suddenly, or something like that. In addition, another important problem that causes some students to lose their chance at an exam is stress. Stress can prevent students to write a good exam, students become nervous and sometimes get headache, stomachache and more. Also, exams cause an improper competition between the students, it is seen even it their families. Hence parents put the students under pressure to get a good grade when criticizing them for bad or not good enough marks on an examination.
Everything that was mentioned about the exam are facts that no one can deny, but not cause enough to abolish exams because of the advantages of examinations. In parts of stress and competition, they are not bad thing all the time, actually stress and competition force the students to keep up with other students specially the lazy ones that are used to postpone their course work. The accident problem, first of all it does not happen every day and if it does it affectss only a few students but not most of them, but a way to solve this problem are midterm examinations. This situation enhance efficiency and reduce stress, competition and likely the accidental problems.
In conclusion, I think examination is a good method to estimate students, and it can be a effective factor to improve knowledge, but it's not enough, so in order to get a more clear picture of the students, it's equally important, if not more important, to have continuous assessment like class activity and projects.