Though some studies like that Hanushek (2011)

Outstanding teachers possess and exhibit many exemplary qualities. They have the skills, subject matter, and pedagogy to reach every child. They help equip their students with the knowledge and breadth of awareness to make sound and independent judgments. Three determinants of teacher quality will be considered here. They are; pedagogical knowledge, subject-matter content knowledge and experience.

3.2 SUBJECT-MATTER KNOWLEDGE

The goal of teaching is to help learners develop intellectual resources that will enable them participate fully in the main domains of human taught and enquiry. The degree to which the teacher can assist students to learn depends on the subject-matter the teacher possesses. That is to say, teachers' knowledge of subject-matter has influence on their efforts to assist students to learn that subject-matter. If a teacher is ignorant or not well informed he/she cannot do students any good, he/she will rather much harm them. When the teacher conceives knowledge in such a way that it is narrow, or do not have accurate information relating to a particular subject-matter, he/she will pass on these same shallow or inaccurate information to students. This kind of teacher will hardly recognize the consistent pre-conceptions and challenge the misconceptions of students. Such a teacher can introduce misconceptions as he/she uses texts uncritically or inappropriately alter them. It is the teacher's conception of knowledge that shapes the kind of questions he/she asks and the ideas he/she reinforces as well as the sorts of tasks the teacher designs.

Teachers' subject-matter matter content knowledge must go beyond the specific topics of their curriculum. This is because the teacher does not only define concepts for students. Teachers explain to students why a particular concept or definition is acceptable, why learners must know it and how it relates to other concepts or definitions. This can be done properly if the teacher possesses a good understanding of the subject-matter. This type of understanding includes an understanding of the intellectual context and value of the subject-matter. The understanding of subject matter generally reinforces the teacher's confidence in delivering lessons, thereby making him/her a good teacher.

3.3 EXPERIENCE

Experience is one of the factors that account for variations in teacher salary, the world over (Hanushek and Rivkin, 2006). The fact that salary differences are based on the number of years the teacher has served, suggests that employers believe the teachers experience makes him/her a better teacher and such a teacher must be motivated to remain in the service. Though some studies like that Hanushek (2011) have suggested that the experience positively influences teacher quality only in the first few years, and that beyond five years, experience ceases to have positive impact on teacher efficacy, common sense tells us the one who has been doing something for a long time does better and with ease. Experience will therefore continue to pay, since, more experienced teachers have the propensity to know more about the subject-matter they teach, and think and behave appropriately in the classroom, and have much more positive attitudes toward their students.