In other words, third-grade scores are probably strongly influenced by poverty and home life, while growth from third to eighth grade is probably more influenced by the quality of schooling. They have little to do with each other:
Growth rates better isolate the contribution to learning due to experiences during the schooling years. Grade 3 average scores are likely much more strongly influenced by early childhood experiences than the growth rates….Some caution is warranted in interpreting the average growth rates as pure measures of school effectiveness. Nonetheless, relative to average test scores (at grade 3 or any grade), the growth rates are closer to a measure of school effectiveness.
If we take the growth rates, then, as rough measures of school effectiveness, then neither socioeconomic conditions nor average test scores are very informative about school district effectiveness. Many districts with high average test scores have low growth rates, and vice versa. And many low-income districts have above average growth rates. This finding calls into question the use of average test scores as an accountability tool or a way of evaluating schools.
Locally, Madison spends far more than most, for average results.