4) Lee et.al (2017) conducted a study aiming to find the relationship between mobile phone addiction and the incidence of poor sleep quality and short sleep duration among adolescents. They used longitudinal data from the Korean Children & Youth Panel Survey conducted by the National Youth Policy Institute in Korea (2011–2013). The data was collected from 1,125 students and the students those who already had poor sleep quality or short sleep duration in the previous year were excluded from the study. Estimating equation which was generalized has been used to analyze the data. Results indicated that high mobile phone addiction increased the risk of poor sleep quality but not short sleep duration.