In a large-scale study of primary schools in the Jerusalem area, yair(1997, p.241) showed that:’the net effect of classrooms is significantly higher than the effect of school, since within-school variability outweighs between-school variability.’
Effectiveness may even consider the level of the individual student. There is little research as to why pupils in the same school have ‘very different experiences of schooling’ (Gray, 1998. P.23)
Effectiveness research has tended to look only at outcome measures. The obvious weakness of this is that it take no account of the ‘value-added’ by the schools. If outcome measures are to indicate effectiveness, some account must be taken of a range of factors that may include the following (Sammons et al., 1994, p.4):