Corrigendum to Assessing the Effects of Gamification in the Classroom: A Longitudinal Study on Intrinsic Motivation, Social Comparison, Satisfaction, Effort, and Academic Performance Computers & Education 80 (2015) Pages 152-161 (Assessing the effects of gamification in the classroom: A longitudinal study on intrinsic motivation, social comparison, satisfaction, effort, and academic performance (2015) 80 (152–161), (S0360131514002000) (10.1016/j.compedu.2014.08.019))