The impact of more teachers and smaller classes in the early years

What difference do smaller class sizes, and more teachers, make in early childhood education (ECE)?

A meta-analysis by Jocelyn Bowne and colleagues, published in Educational Evaluation and Policy Analysis, attempts to find some answers. The analysis included evaluations of ECE programs in the US between 1960 and 2007. The evaluations were either experimental studies, used a high-quality quasi-experimental design, or showed baseline equivalence of treatment and control participants. In total, 38 studies were included, all of which looked at children ages 3 to 5 years old attending an ECE center for 10 hours a week or more for at least 4 months. Child-teacher ratios ranged from 5:1 to 15:1 and class sizes from 11 to 25.

The findings were as follows:

  • Above a child–teacher ratio of 7.5:1, changing the ratio had no effect on children’s cognitive and achievement outcomes. Below this, a reduction of the ratio by one child per teacher predicted an effect size of +0.22.
  • For class sizes greater than 15, increasing the size of the class had little effect on children’s cognitive and achievement outcomes. Below this, one child fewer in the class size predicted an effect size of +0.10.

The authors caution that these findings are correlational, rather than causal, so changing class sizes or ratios, certainly at scale, may not lead to these results. However, they conclude that “very small and/or well-staffed classrooms might confer some small benefits for children’s cognitive and academic learning”.

Source: A meta-analysis of class sizes and ratios in early childhood education programs: Are thresholds of quality associated with greater impacts on cognitive, achievement, and socioemotional outcomes? (February 2017), Educational Evaluation and Policy Analysis, Vol 39, Issue 3

Test results don’t show how effective teachers are

A new study has looked at the link between instructional alignment (how teaching is aligned with standards and assessments), value-added measures of teacher effectiveness, and composite measures of teacher effectiveness using multiple measures.

The issue is important as, in the US and around the world, there is more emphasis on measuring teacher effectiveness and rewarding effective teachers. The study looked at 324 teachers of fourth and eighth grade (Year 5 and Year 9) mathematics and English language arts in five US states. They completed a Survey of Enacted Curriculum to measure their instructional alignment. This was then compared with value-added measures (taken from state assessments and two supplementary assessments) and teacher effectiveness (using Framework for Teaching scores, widely used by states).

The results showed modest evidence of a relationship between instructional alignment and value-added measures, although this disappeared when controlling for pedagogical quality. The one significant relationship they found was that the association between instructional alignment and value-added measures is more positive when pedagogy is high quality. There was no association between instructional alignment and measures of teacher effectiveness.

These results suggest that the tests used for calculating value-added measures are not able to detect differences in the content or quality of classroom teaching.

Source: Instructional Alignment as a Measure of Teaching Quality (2014), Education Evaluation and Policy Analysis, online first, May 2014.