Development and validation of the smartphone use scale

The aim of this study was to develop a self-administering scale that could measure smartphone use. In addition, the reliability and validity of the Smartphone Use Scale (SUS) was demonstrated. A set of 30 questions pertaining to smartphone use were developed with the help of experts. A total of 372 participants were selected to accomplish a set of questionnaires –Smartphone Use Scale (SUS) and Smartphone Addiction Scale (SAS) (Kwon, Lee, Won, Park, & Min, 2013). The sample comprised 182 males and 190 females, with ages ranging from 16 to 22. Internal-consistency test and correlation analysis were conducted to verify the reliability and validity of SUS. Reliability and concurrent validity of the test were computed. Cronbach's alpha was found to be 0.712. Concurrent validity using the SAS was found to be 0.76. The study shows that 13.72% males and 14.28% females fall under the “high smartphone use” category, 63.72% males and 63.47% females were found to be under the “average smartphone use category, and 22.54% males and 21.73% females were found to be under the “low smartphone use” category.

expensive than feature phones. However, according to a survey by Nielsen India, 50% of those 40 million smartphones are with people under the age of 25. Regarding the usage of smartphones, a study by Nielsen Informate Mobile Insights (Smartphone Incidence Study, 2013), found that on an average, Indian smartphone users spend 2 hours and 30 minutes with smartphones and 72% of that time goes into gaming, entertainment, and Internet. Traditional voice calls and text messaging take a mere 28% of the time. Younger Indians prefer to spend most of their time browsing the internet on their smartphones with little time spent for SMS. Casual browsing of the phone like searching for contacts and setting alarms take 30 minutes of the time for 15-24 year olds.
The smartphone has many functions that are viewed as essential in today's world. In such a setting, it is very difficult to distinguish between smartphone use and smartphone over-use. Smartphone over-use, or problematic smartphone use can thus be determined using the same yardsticks that are used to measure abuse of other addictive objects or substances. When smartphone use reaches a level where it starts interfering and hampering personal and occupational functioning, it may be categorised as over-use.
The criteria for substance abuse as per DSM-IV-TR (APA 2000): 1. recurrent use leading to failure to fulfil major obligations 2. recurrent use which is physically hazardous 3. recurrent legal problems related to use 4. continued use despite social or interpersonal problems 5. The symptoms have never met the criteria for dependence The criteria for Other (or unknown) Substance Use Disorder as per DSM-5 (APA 2013): 1. The substance is often taken in larger amounts or over a longer period than was intended. 2. There is a persistent desire or unsuccessful efforts to cut down or control use of the substance. 3. A great deal of time is spent in activities necessary to obtain the substance, use the substance, or recover from its effects. 4. Craving. Or a strong desire or urge to use the substance. 5. Recurrent use of the substance resulting in a failure to fulfill major role obligations at work, school, or home. 6. Continued use of the substance despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of its use. 7. Important social, occupational, or recreational activities are given up or reduced because of use of the substance. 8. Recurrent use of the substance in situations in which it is physically hazardous. 9. Use of the substance is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by the substance.
The people who have problematic smartphone use have many signs in common with the criteria for Substance Use Disorder (Brewer, Elwafi, & Davis, 2013): 1. Texting while driving 2. Facing problems at work or in relationships due to excessive phone usage 3. Extreme anxiety when separated from their smartphones 4. Using the smartphone for a longer duration than intended 5. Having a strong desire to use the smartphone when it is not supposed to be used. 6. Feeling phantom vibrations -the feeling that the phone is vibrating, when it is not.
Indians are catching up with their western counterparts in terms of smartphone ownership and use, warranting research about the patterns and effects of smartphone use among them to predict and prevent addiction and overuse.
Sample 182 males and 190 females (age= 16-22 years), from Kolkata, belonging to the High Income Group families (income above Rs. 40,000 p.m.) served as samples for the present study.
Participants of the study belonged to nuclear families, had internet connection at their own residence, and minimum duration of smartphone ownership was 6 months. Students from broken homes and those staying away from home were excluded from the study.

Information schedule:
An information schedule seeking personal, familial, and smartphone usage information was used for data collection.

Procedure
The aim of the present study is to develop a scale to measure smartphone use, and to test the reliability and validity of the scale. This scale was prepared by developing statements related to various aspects of smartphone use, such as duration of use per day, reaction upon not having the smartphone in possession, circumstances under which the smartphone is used most, etc. 40 statements were shortlisted for relevance rating by experts, following which a final list comprising 30 statements were chosen for the data sheet to be filled by participants of the study. The scale follows a 5-point Likert format (ranging from 1-5. The statements were divided along five dimensions -smartphone use and interpersonal relationships, smartphone as a precious possession, smartphone as a companion, smartphone as a tool for evasion, smartphone as an instrument of multiple utility. Data was collected from 200 males and 200 females of the age group 16-22. After rejecting incomplete data sheets and those that did not meet the inclusion criteria, a final 372 (182 males and 190 females) data were selected. Reliability was measured by computing Cronbach's Alpha. For validity of the scale, the Smartphone Addiction Scale (Kwon M, Lee J-Y, Won W-Y, Park J-W, Min J-A., 2013) was administered to the same participants, and their scores on the SAS and SUS were correlated.   The present study found that, 13.72% males, and 14.78% females fall under the category of High Smartphone Use. The mean score for males was found to be 92.69, and the mean score for females was found to be 92.46. Both these mean scores lie above the median score, which is 90. Overall mean of the Smartphone Use Scale was found to be 92.56, which is also above the median score. Overall standard deviation was found to be 14.46. On the basis of mean scores for males and females, norms of the Smartphone Use Scale are: Internal consistency of the Smartphone Use Scale was measured using Cronbach's Alpha which was found to be 0.712, which indicates reasonably good reliability. Correlation between the Smartphone Addiction Scale and the Smartphone Use Scale was found to be 0.763, which indicated reasonably good validity of the SUS.