Cross-cultural adaptation and psychometric properties of the Korean Scale for Internet Addiction (K-Scale) in Japanese high school students

Kwok Kei Mak, Jee Eun Karin Nam, Dongil Kim, Narae Aum, Jung Seok Choi, Cecilia Cheng, Huei Chen Ko, Hiroko Watanabe

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13 Scopus citations


The Korean Scale for Internet Addiction (K-Scale) was developed in Korea for assessing addictive internet behaviors. This study aims to adopt K-Scale and examine its psychometric properties in Japanese adolescents. In 2014, 589 (36.0% boys) high school students (Grade 10–12) from Japan completed a survey, including items of Japanese versions of K-Scale and Smartphone Scale for Smartphone Addiction (S-Scale). Model fit indices of the original four-factor structure, three-factor structure obtained from exploratory factor analysis (EFA), and improved two-factor structure of K-Scale were computed using confirmatory factor analysis, with internal reliability of included items reported. The convergent validity of K-Scale was tested against self-rated internet addiction, and S-Scale using multiple regression models. The results showed that a second-order two-factor 13-item structure was the most parsimonious model (NFI=0.919, NNFI=0.935, CFI=0.949, and RMSEA=0.05) with good internal reliability (Cronbach's alpha=0.87). The two factors revealed were “Disturbance of Adaptation and Life Orientation” and “Withdrawal and Tolerance”. Moreover, the correlation between internet user classifications defined by K-scale and self-rating was significant. K-Scale total score was significantly and positively associated with S-Scale total (adjusted R2=0.440) and subscale scores (adjusted R2=0.439). In conclusion, K-Scale is a valid and reliable assessment scale of internet addiction for Japanese high school students after modifications.

Original languageEnglish
Pages (from-to)343-348
Number of pages6
JournalPsychiatry Research
StatePublished - 1 Mar 2017

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© 2017


  • Adolescents
  • Internet Addiction
  • Smartphone Addiction


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