Researchers followed these individuals for an average of eight years and, based on self - reported amounts of weekly exercise, placed them into five categories. (criticalillnessinsuranceinfo.org)
The study also only looked at school - wide scores without following individual students in the voucher program. (washingtonexaminer.com)
The panel dataset I create follows these individuals from age 25 through age 65. (educationnext.org)