These tests have low validity, low reliability and are less comprehensive. Discussing about the weaknesses of this type of tests Ross remarks,
“The essay overrates the importance of knowing how to say a thing and under-rates the importance of having something to say”.
This type of tests are not reliable because there is no agreement between teachers about the marks to be assigned and studies have shown that even the same teachers do not agree with themselves.
Sanford, in his book on educational psychology refers to a study, “In one department of the University of Toronto, the same subject was set for an essay in different years. The essay which had secured 80 marks in one year was exactly copied by the students in another year and scored 39 marks”.
Ashburn who carried out a study at University of West Virginia concluded that, “the passing or failing of about 40% depends not on what they know or do not know, but on who reads the papers and that the passing or failing of about 10% depends on when the papers are read”.
Another general complaint of students about essay type tests is that the questions ‘did not suit them’. Certainly nine or ten questions generally set in this type of question paper cannot cover the whole syllabus. Hence this type of test is less comprehensive.
In an effort to offset the disadvantages the teacher must carefully consider the construction of each essay question. The teacher should word the question in such a fashion that the pupil will be limited to a certain degree to the concepts being tested. For example, it is better to use:
If you move to Greenland, how would the days and nights differ from where you live now? How would the season differ?
Discuss the differences between the places in the world in relation to their days and nights throughout the seasons.
The second question is much too broad and does not give the pupil direction to know clearly enough what is expected?
To minimize the shortcomings of excessive subjectivity teacher should prepare a scoring guide beforehand. Each question be scored separately and a list of important ideas that are expected should be made.