I have a new paper on teacher effectiveness out today. So far as I know, it's the first ‘value-added’ study to be conducted outside the United States.

Estimating Teacher Effectiveness From Two-Year Changes in Students Test Scores
Using a dataset covering over 10,000 Australian primary school teachers and over 90,000 pupils, I estimate how effective teachers are in raising students[base '] test scores from one exam to the next. Since the exams are conducted only every two years, it is necessary to take account of the work of the teacher in the intervening year. Even after adjusting for measurement error, the resulting teacher fixed effects are widely dispersed across teachers, and there is a strong positive correlation between a teacher[base ']s gains in literacy and numeracy. Teacher fixed effects show a significant association with some, though not all, observable teacher characteristics. Experience has the strongest effect, with a large effect in the early years of a teacher[base ']s career. Female teachers do better at teaching literacy. Teachers with a masters degree or some other form of further qualification do not appear to achieve significantly larger test score gains. Overall, teacher characteristics found in the departmental payroll database can explain only a small fraction of the variance in teacher performance.

The results imply that a 75th percentile teacher can achieve in three-quarters of a year what a 25th percentile teacher can achieve in a full year; and that a teacher at the 90th percentile can achieve in half a year what a teacher at the 10th percentile can achieve in a full year. For what it' worth, I don't think this dispersion is wider than what one would find among plumbers, dentist, architects or bricklayers. But it does indicate that - at least as measured by test score gains - all teachers are not created equal.

One context in which this might especially matter is with regard to Indigenous children. In the paper, I estimate that Indigenous primary school students perform approximately two grades below their non-Indigenous counterparts. Assuming that the impact of having a more effective teacher persists over time, and that Indigenous children typically get teachers at the 25th percentile, these results imply suggests the black-white test score gap in Australia could be closed in seven years by giving all Indigenous pupils teachers at the 75th percentile.

7:49:56 PM