Reassessing the smartphone addiction scale: Support for unidimensionality and a shortened scale from an American sample

Highlights

• The underlying factor structure of the SAS was thoroughly examined.

• Survey data from a sample of 1155 U.S. undergraduate students were analyzed.

• The original 33-item SAS is not a multidimensional but unidimensional instrument.

• The original 6-category rating scale could be replaced by a 4-category one.

• A 10-item shortened SAS scale is presented with robust psychometric properties.

Abstract

This study examined the multidimension assumption of the often-used 33-item, six-factor Smartphone Addiction Scale (SAS) by employing four confirmatory factor models (i.e., one-factor, first-order six-factor, second-order six-factor, and bifactor). Survey data were collected from 1155 undergraduate students in a US public university. Findings showed that the bifactor model was the best fitting model and SAS is a unidimensional instrument. The composite scores made for the six domain-specific factors, often seen in the literature, were not reliable measures for the construct of smartphone addiction and can result in misleading or even incorrect inferential test results. The most reliable and contributing items identified by the bifactor model were selected to form a short, more efficient version of SAS. A Rasch model was performed to test the psychometric properties of the shortened SAS. The new shortened SAS contains 10 items (SAS-10) and had good reliability, construct validity, and no presence of bias towards students in different gender or academic achievement groups. Additional evidence suggests a 4-category rating scale is enough to capture the construct of smartphone addiction. Finally, SAS-10 correlated to numerous external criterion variables similarly to how the extant literature would predict. SAS-10 is provided in appendix C.

Introduction

The American Psychiatric Association defines addiction as “a complex condition, a brain disease that is manifested by compulsive substance use despite harmful consequences” (American Psychiatric Association, 2013, p. 1). However, a broader definition has gained increasing acceptance. According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V; American Psychiatric Association, 2013) and the International Classification of Diseases (ICD-11; World Health Organization, 2018), the concept of addiction covers non-substance/behavioral dependence, including gambling and Internet Gaming Disorder. In line with this, Kardefelt-Winther et al. (2017) defined behavioral addiction with two components: (1) significant functional impairment or distress as a direct consequence of the behavior and (2) persistence over time.

Despite mixed opinions regarding whether persistent smartphone use can be defined as one type of addiction (Billieux, Maurage, Lopez-Fernandez, Kuss, & Griffiths, 2015; Yu & Sussman, 2020), a large and growing body of literature has demonstrated functional impairment and distress due to persistent smartphone use and suggested the concept of smartphone addiction (Busch & McCarthy, 2021). Psychopathological correlates of smartphone addiction include depression severity, anxiety, and stress (Elhai, Dvorak, Levine, & Hall, 2017). Users addicted to smartphones tend to suffer from sleep disturbance (Li et al., 2020), blurred vision, neck pain (Kwon, Lee, et al., 2013; Xie et al., 2016), low physical activity (Saffari et al., 2022), greater sedentary behavior (Barkley et al., 2016), and lower quality of life (Buctot, Kim, & Kim, 2020). In addition to mental and physical health problems, smartphone overuse may lead to changes in attitude towards school or work, which in turn results in poor academic or work performance (Chen et al., 2017; Chung et al., 2018; Kwon, Lee, et al., 2013; Lepp et al., 2014). Collectively, evidence from previous research clearly indicates negative risk factors associated with excessive smartphone use. Hence, by drawing on the conceptualization of Kardefelt-Winther et al. (2017), this study adopted the view that smartphone overuse can be an addictive behavioral disorder as it shares many similarities with other addictive technological behaviors, such as Internet gaming disorder (Panova & Carbonell, 2018).