To understand the problem, Njengere said that a look at how the KCSE is designed is critical. He observed that the examination was curated to serve a dual role.
The first, Dr Njengere said, is to rate the learners' achievement over the four years period in secondary school. The second role, he said, is that it acts as a transition marker that determines where the student proceeds; that is either college or university.
The latter, however, Dr Njengere said, has been a thorn in the flesh of many Form Four leavers as the grading system waters down their general performance.
He said the ripple effect leads to locking out thousands from pursuing education further than secondary school.
Njengere said that due to cut-throat competition in the final examination, KCSE has been reduced to an examination that decides where the student proceeds and ignores the assessment purpose.
"The demands of the curriculum are not supposed to inhibit you in any way from transitioning because you must transition in life, whether because of age or achievement," Dr. Njengere said in an interview with the Standard on Wednesday.
Giving an example, he said a candidate inclined towards the social sciences must deal with two science subjects, which they must pass because if they fail those two, then it waters down the final score and risks locking them out of their dream course.
"So it doesn't matter how good I am in my languages and humanities, these three will bring me down, so I will end up with a mean score that will give me an aggregate of a C or something, not because I am foolish but because of the demands of the system," Dr. Njengere said.
He added: "We are punishing the students. For example, a student who is very good in sciences, we tell him/her that you must pass in English, you must pass in humanities, and so on; the kid can't do that, so we are creating wastage in the system."
The same case scenario applies to students who are more inclined to Sciences, who have to be assessed in English and Literature, Kiswahili and Fasihi.
"In essence, what the Presidential working party is asking, is it necessary that at the point you are exiting secondary school, some subjects pull you down when you want to pursue a specific line that does not necessarily require that you must pass at a very high level in all these subjects.
Dr Njengere says all subjects are important even for students who do not necessarily need the subjects in their careers for core knowledge such as numeracy and literacy.
However, he insists that there must be a distinct separation between achieving this core knowledge and grading the learner when they sit for KCSE exams.
"On achievement, we will assess you because you need to have some fundamental knowledge in numeracy, literacy," he said. It is emerging that the present grading system has ranked Kenya below other countries.
Analysis of data from the East Africa region, for example, shows that Kenya ranks lowest in the number of top grades, otherwise referred to as distinctions - that is Grade A and A- (minus) in the final national examination.
In contrast, Kenya's performance plummeted with only 0.85 per cent. This means only 7,553 candidates managed to get a Grade A or A- (minus), the equivalent of a distinction in Uganda and Tanzania.
"This is where you start telling yourself that the problem may not be the students but the system we are using to grade our children. Perhaps we are using a system that is a little too punitive for them, and we are not separating achievement from placement," Dr. Njengere said.
Another comparison between the performance of the final secondary school exam under the 8-4-4 and the education system preceding it, the 7-4-2-3 education system:
The analysis shows that between 1983 and 1986, some 3,509 candidates (equivalent to 3.21 per cent of those who sat the exams) got Division 1, the topmost grade at O-levels.
However, upon the adoption of the 8-4-4, the numbers dropped drastically.
In 1989 for example, only one student out of 130,639 candidates scored Grade A in KCSE. In the following year, 1990 there were 131,932 candidates but none scored an A. And in 1991, the candidature rose to 166,712 out of which only two scored an A.
Even with the undertones of examination cheating and malpractice that raged before the reforms of 2016, data from the Knec shows the best results were in 2014, but even then, only 0.635 per cent of the total candidature scored an A.
"Let's assume that there was this massive cheating that happened, we could not get even one percent of the total candidate population getting the topmost grade," he said.