What’s the difference between kids who read more than 30 minutes per day and those who read less than 15 minutes per day?
Vocabulary exposure that is greater by twelve million words.
Between kindergarten and twelfth grade, students with an average daily reading time of 30+ minutes are projected to encounter 13.7 million words. At graduation, their peers who averaged less than 15 minutes of reading per day are likely to be exposed to only 1.5 million words. The difference is more than 12 million words.
source: https://www.renaissance.com/2018/01/23/blog-magic-15-minutes-reading-practice-reading-growth/