Effects of Good Teachers on Student Outcomes

These findings would suggest that the difference in achievement gains between having a 25th percentile teacher (a not so effective teacher) and a 75th percentile teacher (an effective teacher) is over one-third of a standard deviation (0.35) in reading and almost half a standard deviation (0.48) in mathematics. Similarly, the difference in achievement gains between having a 50th percentile teacher (an average teacher) and a 90th percentile teacher (a very effective teacher) is about one-third...

 Mindfulness Programs Improves Learning

This is the first systematic review and meta-analysis to summarize data available on the effects of mindfulness-based trainings for children and youths in a school setting. Twenty-four studies were located that report a significant medium effect size of g = 0.40 across all controlled studies and domains. Remarkably, the ES of studies using pre-post designs only is very similar, with g = 0.41. The effects are strongest in the domain of cognitive performance with a large and significant ES of g...

 Iodization of Salt in 1924 Increased American IQs 15 Points

Iodine deficiency is the leading cause of preventable mental retardation in the world today. The condition, which was common in the developed world until the introduction of iodized salt in the 1920s, is connected to low iodine levels in the soil and water. We examine the impact of salt iodization on cognitive outcomes in the US by taking advantage of this natural geographic variation. Salt was iodized over a very short period of time beginning in 1924. We use military data collected during W...