A number of diagnostic scales have been developed in recent years to assess Internet addiction. To better understand the structure, validity, and reliability of such assessment instruments, Young’s Internet Addiction Test (IAT) was evaluated using a confirmatory approach.

Data collected through a survey of 410 Hong Kong university undergraduates was subjected to exploratory factor analysis and data from a hold-out sample was analyzed using confirmatory factor analysis in order to assess the psychometric properties and factor structure of the IAT scale. Three dimensions, namely, “Withdrawal and Social Problems”, “Time Management and Performance”, and “Reality Substitute” were extracted.

These dimensions were then correlated with a number of criterion variables, including academic performance, online activities, gender, and Internet usage. The results show that academic performance was negatively correlated with the Internet addiction scores. The degree of Internet addiction was also found to vary across different types of online activity, with people engaged in cyberrelationships and online gambling having higher Internet addiction scores.

Keywords: Internet addiction; Young’s Internet Addiction Test; Confirmatory factor analysis

The 21st century promises to be a digital era when technologies, especially the Internet will have a profound influence on daily life. The Internet has already changed our life enormously, and the benefits brought about by such a powerful tool are obvious to all. Nevertheless, many studies have suggested that people may use the Internet addictively and that this can exert harmful effects on individuals, altering their social behavior, habits and abilities in a negative way ([Chen et al., 2004], [Stanton, 2002] and [Young, 2004]).

Researchers studying the problems related to Internet use have adopted different terminologies such as Internet addiction, Internet addiction disorder, Internet dependence, problematic Internet use, or pathological Internet use to describe the negative effects of excessive Internet use on personal lives ([Chen et al., 2004],[Chou and Hsiao, 2000], [Davis, 2001], [Goldberg, 1995], [Griffiths, 1998], [Kandell, 1998], [Morahan-Martin and Schumacher, 2000], [Scherer, 1997], [Shaffer, 1996] and [Young, 1998a]). Young (1996) has linked excessive Internet use to DSM-IV criteria (American Psychiatric Association, 1994) and considered it a behavioral addiction similar to pathological gambling. She characterizes Internet addiction as an impulse-control disorder that mainly involves psychological dependence on the Internet (Young, 2004). Although there is no standard definition to date, the phenomenon is commonly conceptualized as the compulsive behavior and cognitions associated with Internet use which results in marked distress in daily life ([Caplan, 2002], [Shapira et al., 2000] and [Young, 1996]).

Increased interest in Internet addiction has prompted the development of instruments like the Internet Addiction Test (Young, 1998a), the Pathological Internet Use scale (Morahan-Martin & Schumacher, 2000), and the Generalized Problematic Internet Use Scale (Caplan, 2002) for assessing Internet use behavior. To better understand the phenomenon, it is crucial to establish the validity and reliability of such instruments. This study attempted to evaluate one of the instruments: Young’s (1998a) Internet Addiction Test (IAT).

Young and her associates have done a lot of work on defining Internet addiction (Yellowlees & Marks, 2007), and the IAT is one of the early diagnostic scales that has been developed. Although the IAT was developed ten years ago, it is still employed in recent studies to investigate important phenomena such as the relationship between different kinds of addictions (Pallanti, Bernardi, & Quercioli, 2006), psychiatric comorbidity ([Ha et al., 2006] and [Yang et al., 2005]), and other correlates with Internet addiction ([Ferraro et al., 2007] and [Li and Chung, 2006]).

The IAT has demonstrated strong internal reliability across studies (e.g., [Widyanto and McMurran, 2004], [Yang, 2001], [Yang et al., 2005] and [Young, 1998a]). While the overall reliability of the IAT scale as measured by Cronbach’s alpha has been good in these studies, there is a paucity of research that assesses the factor structure of the IAT, and thus analyzes Internet addiction as a multi-dimensional construct. Dimensionality assessment is important because the definition of instrument structure is a prerequisite to subsequent instrument refinement and failure to identify the dimensionality of the scale may lead to inaccurate specifications of theories (Smith & McCarthy, 1995). Moreover, the subscales can provide a greater level of detail than just utilizing Internet addiction as one overall concept. For instance, people may suffer different severity of negative impacts in different aspects of Internet addiction. Knowing this helps us to focus treatments on the area that requires special attention. Consequently, the factor scores can provide information beyond that obtained from the global score of the entire scale (Floyd & Widaman, 1995).

Despite its importance, at the time of our study, only one study with a small sample size of 86 participants could be found to investigate the dimensionality of the IAT (Widyanto & McMurran, 2004). Hence, the present study aimed to examine, refine and validate the dimensionality of the IAT instrument using a confirmatory approach.