It shall be the policy of the District to evaluate student achievement in grades kindergarten through 12. The extent of each student's progress toward school-adopted goals shall continually be of central concern to the school staff. Within the assumptions inherent in the grading system, a student's progress shall be viewed comprehensively in light of such factors as the student's age, mental health, social needs, level of maturity, ability as determined by objective and subjective data, educational achievement, and environmental influences.