Health Promotion and Treatment
Reliability and Validity of the Greek Version of the Smoking Self-Efficacy Scale for Adolescents
Evaluation & the Health Professions 2015, Vol. 38(1) 126-139 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0163278713520450 ehp.sagepub.com
Nikos Zourbanos1, Eleni Dimitriou1, Marios Goudas1, and Yannis Theodorakis1
Abstract This study examined the psychometric properties of the Greek version of the Smoking Efficacy Scale (SES) for adolescents in a sample of 536 high school students. The factorial structure of the SES was examined by means of a series of exploratory factor analyses. The structural validity, the internal consistency, the temporal stability, and the concurrent validity of the SES were assessed. Exploratory and confirmatory factor analyses revealed a clear three-factor (emotion, opportunity, and friends) structure. Furthermore, SES predicted students’ smoking behavior. Overall, the multidimensionality of the SES was supported by our findings, suggesting that the Greek version of the SES appears to be a psychometrically sound
Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
Corresponding Author: Nikos Zourbanos, Department of Physical Education and Sport Science, University of Thessaly, Karyes, Trikala 42100, Greece. Email: [email protected]
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instrument that can be used for the evaluation of smoking prevention and smoking cessation programs for high school students. Keywords assessment, students, smoking, validity, self-efficacy
Smoking is the worldwide leading cause of preventable illness and death and one of the possible causes of many fatal diseases such as lung cancer, heart disease, and stroke (World Health Organization [WHO], 2008). In the 20th century, the tobacco epidemic killed 100 million people worldwide. Greece, along with Chile and Ireland, shows the highest smoking rates among the member countries of the Organization for Economic Co-operation and Development (OECD). In Greece, it is estimated that 30% of the adult population is exposed to daily smoking (OECD, 2013) and approximately 19,000 people per year die from smoking-related diseases (Behrakis & Connolly, 2011). In comparison with adult smoking, information on youth smoking rates in Greece is limited. According to the most recent report of WHO (2011), the prevalence of tobacco use in adolescents aged 13 to 15 years was 17% for males and 14% for females (data from 2005 to 2008). Many theories may be employed for developing interventions attempting to change poor health behavioral patterns such as tobacco smoking. One of the most widely used theories is the theory of self-efficacy by Bandura (1986, 1997). The concept of self-efficacy may be employed in studies designed to explore the contribution of the level of confidence in the prediction of resistance to smoking. Therefore, the purpose of this study was to translate and validate the Smoking Efficacy Scale (SES) of Lawrance (1989) in the Greek language in order to develop a valid measure toward the prediction of smoking behavior in Greek adolescents. The definition of smoking behavior is different in children in comparison with the adults. An adult smoker is typically defined as the adult who has smoked at least 100 cigarettes in his or her lifetime and who smokes on most or all days of the week. A child smoker is defined as the child who has smoked even one cigarette in the previous 30 days (Centers for Disease Control and Prevention [CDC], 2009). In 2003, 37.6% of the Greek population were smokers (males: 46.8% and females: 29.0%) with an annual per capita consumption of 2,977 cigarettes (European Commission & Statistical Office of the European Communities, 2003). In 2010, the annual per capita consumption fell to 2,458 cigarettes due to clean air laws and tax increases
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(as cited in Behrakis & Connolly, 2011). Filippidis et al. (2013) have also reported that the trends in smoking prevalence and consumption in Greek adults declined after the implementation of the 2010 smoke-free legislation. Nevertheless, Greece maintains one of the highest per capita consumption rates of tobacco products in the European Union. Although smoking rates have declined in Greek adults, they are still high in adolescents. The Global Youth Tobacco Survey examined the prevalence of smoking among 6,378 middle school students in Greece aged 13–15 (Kyrlesi et al., 2007). Results showed that 32.2% of the students had smoked at least once and approximately one of the four students of both genders had initiated smoking before the age of 10. Similarly, Arvanitidou et al. (2008) examined a sample of 1,221 adolescents aged 14 to 18 years and reported a higher percentage of cigarette smoking for girls compared to boys (40.9 vs. 34.3%), with boys presenting a slightly earlier initiation of tobacco use (12.7 vs. 12.9 years in girls). Smoking rates in Greek adolescents vary across different regions (Vardavas & Kafatos, 2006). Specifically, in a sample of 18,904 participants with a mean age of 15 years, Spyratos et al. (2012) found that students living in urban and semirural areas smoke more frequently than those in rural areas. Collectively, the prevalence of smoking in Greek adolescents is high representing a significant public health problem. It is therefore vital to develop public health programs toward smoking prevention. The relationship between psychosocial factors and smoking behavior is complex and involves a number of risk factors. Risk factors associated with cigarette smoking in adolescents include gender, age range, and having peers and/or parents who smoke (e.g., Hublet et al., 2006). One of the most widely used theories employed by health researchers to improve health behavioral patterns is the social cognitive theory. This theory includes the self-efficacy concept (Bandura, 1986, 1997). Self-efficacy represents a significant indicator of motivation in studies designed to explore or enhance individual’s self-control. The term ‘‘efficacy’’ is an individual’s objective ability to perform a specific behavior. Bandura (2004) defined efficacy beliefs as those beliefs ‘‘ . . . that enable adolescents to manage the emotional and social pressures to adopt detrimental health habits’’ (p. 158). Noteworthy, high self-efficacy beliefs prevent youth smoking initiation, facilitates smoking cessation in high school students (Chang et al., 2006), and is the first predictor for smoking cessation in the contemplation stage (Badr & Moody, 2005). Although importance of self-efficacy plays an important role in antismoking strategies for youth, the majority of studies have measured
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teenagers’ smoking self-efficacy with the instruments developed in and for the adult population. Delveno, Lewis, Kaufman, and Abatemarco (2004) suggested that this approach should not be considered as always reliable and valid. Thus, Condiotte and Lichtenstein (1981) and Lawrance and Rubinson (1986) developed the SES. This SES was later modified by Lawrance (1989) in order to reflect age-related differences for the adolescent population. In particular, Lawrance (1989) examined the validity and reliability of the SES in an attempt to predict smoking behavior in 567 seventh-grade students in urban schools across three different time periods. Factor analysis identified three factors for the SES, including opportunity to smoke, emotional stress, and friends’ influence with a factor loading for each item of .60 or higher at each of the three different time periods. Also, high internal consistency coefficients were reported (Cronbach’s a coefficients for the three subscales ranged from .94 to .97), and test–retest correlations for the three subscales (r > .89) provided further evidence of reliability (Lawrance, 1989). Accordingly, concurrent and predictive validity properties suggested the application of the SES in the prediction of smoking behavior. The majority of the studies have used the SES to examine the onset of smoking behavior and the self-efficacy contribution to quit smoking in young adolescents. Huver, Engels, and Hein de Vries (2006) used the SES to examine the effects of antismoking parenting practices on adolescents’ smoking initiation. Antismoking practices were associated with adolescents’ attitudes toward smoking, perceived social influences, and self-efficacy expectations. Also, Patten et al. (2008) used the same scale to examine selfefficacy in adolescents receiving a clinic-based brief intervention for smoking cessation. A significant increase in the self-efficacy to quit smoking at posttreatment was recorded. Both of these studies suggest that the SES contributes to the prediction of smoking behavior in adolescents. The SES, however, is not available in the Greek language. Therefore, the aim of this study was to translate and culturally adapt the SES for use in Greek adolescents. Based on the English version of the SES for adolescents, the psychometric properties of the Greek version of the SES were assessed in order to predict smoking initiation in young Greek adolescents. It was hypothesized that the Greek version of the SES would have the same three-factor structure with the original version of the SES and an adequate internal consistency and test–retest reliability. In terms of concurrent validity, we anticipated that the Greek version of the SES would be adversely associated with the reported smoking behavior.
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Method Participants Three samples were recruited. Each sample consisted of high school students aged between 16 and 17 (M ¼ 16.3, SD ¼ 1.2). In the first sample (n ¼ 124; 68 girls and 56 boys; randomly selected from 6 different classes of 3 different schools), we examined the factorial structure of the first version of the translated SES. In the second sample (n ¼ 116; 56 girls and 60 boys; randomly selected from 5 different classes of 2 different schools), we assessed the factorial structure of the revised version of the questionnaire. Finally, in the third sample (n ¼ 296; 144 girls and 152 boys; randomly selected from 14 different classes of 5 different schools), we reexamined the structure of the SES questionnaire using confirmatory factor analyses (CFA), the internal consistency, the temporal stability (n ¼ 45), and concurrent validity.
Measures Self-efficacy to Resist Smoking for Adolescents. This self-reported questionnaire assesses students’ self-efficacy to resist smoking. The scale includes 36-items describing social and emotional conditions in which adolescents are likely to smoke. In the headline of the questionnaire the item ‘‘How certain do you feel that you could RESIST smoking when . . . .’’ introduced the student to the aim of this research. Students were required to rate their reaction to each situation described in each item on a 5-point scale, ranging from 1 (not at all sure) to 5 (absolutely sure). Instead of using the scale of the original instrument that rates from 1 (I am very sure I would smoke) to 6 (I am very sure I would NOT smoke), we selected this particular rating scale (see in the Procedure section for more details). Lawrance (1989) reported for this scale (1) a three-factor solution with factors named: emotional, friends, opportunity, and (2) a Cronbach’s a for the three factors ranging from .94 to .97, indicating high internal consistency (the factor loadings > .60 were used to construct each self-efficacy subscale). Self-Reported Smoking Behavior. To assess students’ smoking behavior, we used eight questions from Theodorakis and Hassandra (2005). The first five questions are answered with a ‘‘yes’’ or ‘‘no’’ and refer to habits of smokers including: (1) lifetime cigarette use: if the individual has ever tried cigarette smoking even one or two puffs; (2) lifetime daily cigarette use: if the individual has ever smoked one or more cigarettes per day for a whole month;
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(3) current cigarette use: if the individual has smoked cigarettes in a day or more of the 30 days preceding the survey; and (4) frequency of cigarette use: if the individual has smoked more than 10 cigarettes per day on at least 20 days over the past 30 days preceding the survey. The last three questions asked the participants of the study to complete the number of cigarettes smoked on average during the previous month, week, and most recently the day before (Kann et al., 2000).
Procedure and Analysis The initial pool of the SES items was translated into Greek by two bilingual secondary school teachers. Back translation was conducted by two other bilingual teachers (for more information, see Harkness, 2003, p. 41). The original English version was then compared with the back-translated version, where errors and discrepancies were identified. The resulting questionnaire was completed by a group of 10 students (6 girls and 4 boys) aged 14–15. The pool of items and the operational definition of the factors were then submitted to 10 experts. These experts were requested to match each of the items with the specified factors and to rate (a) the degree of relevance of each item to this factor on a 7-point scale ranging from 1 (not relevant) to 7 (absolutely relevant) and (b) the degree of clarity of each item on a 7-point scale ranging from 1(not at all clear) to 7 (very clear). Also, these experts were asked to familiarize themselves with the definitions of the categories/factors provided. Regarding the SES scoring, the experts were asked to choose between two rating scales: first, a 5-point scale ranging from 1 (not at all certain) to 5 (absolutely certain) and second, a 6-point scale ranging from 1 (I am very certain I would smoke) to 6 (I am very certain I would NOT smoke). The latter scale was the scale of the original (English) version. Based on the experts’ responses, 22 items were retained for the first Greek version of the SES. Analysis of the discarded items indicated that they were not so relevant to the constructs that they were supposed to be measuring and/or were relevant to other non-keyed constructs. The experts identified potential problems concerning the wording of some items, thus some were removed. Permission regarding the student’s study participation was obtained from head teachers in both surveys. All participants were informed about the confidentiality of the data and their rights to refuse participation. In an attempt to ensure confidentiality and to reduce fear of reprisal, teachers were not present while the survey was being administered. Students were assured that
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the questionnaires were anonymous and that the data would be used solely for research purposes. Finally, the study instructions included an effort to decrease social desirability in the responses. Lawrance (1989) used only the common exploratory factor analysis (EFA) to identify the underlying dimensions of the SES. In the original manuscript (Lawrance, 1989), however, the EFA results were not presented in detail (e.g., criteria for retaining factors). In the present study, both EFA and CFA were employed in order to identify the dimensions of the SES in a wider age group. Lawrance examined the structure of the SES in a sample of seventh-grade students, whereas this study reexamined the structure of the SES by recruiting high school students. This was done in order to evaluate as to whether the specified factor model provides a good fit to the data.
Results Structural Validity and Reliability The version of the SES distributed to the first sample was analyzed through EFA using principal component analysis. The analysis revealed that a threefactor solution should be interpreted. Thus, the three-factor solution was tested using principal axis factoring as well as oblique rotation because factors were correlated. The Kaiser–Meyer–Olkin test (KMO ¼ .93) confirmed the suitability of the data for factor analysis. Three factors emerged and accounted for 78.98% of the total variance. To improve the structural validity of the SES, items with loadings of