The "Days of Learning" Metric for Education Evaluations

The third National Charter School Study aimed to test whether charter school were effective and to highlight outcomes on academic progress. The results showed that typical charter school students outperformed similar students in noncharter public schools by 6 days in mathematics and 16 days in reading. The key metric used to claim better performance in charter schools is "days of learning." In this report, the origin of the days-of-learning metric is explored with NAEP data, and the interpretation of days of learning as within-year growth is considered.