ON QUITTING SMOKING: DEVELOPMENT OF TWO SCALES MEASURING THE USE OF SELF-CHANGE STRATEGIES IN CURRENT AND FORMER SMOKERS (SCS-CS AND SCS-FS)

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1 Pergamon Addictive Behaviors, Vol. 25, No. 4, pp , 2000 Copyright 2000 Elsevier Science Ltd. Printed in the USA. All rights reserved /00/$ see front matter PII S (00)00068-X ON QUITTING SMOKING: DEVELOPMENT OF TWO SCALES MEASURING THE USE OF SELF-CHANGE STRATEGIES IN CURRENT AND FORMER SMOKERS (SCS-CS AND SCS-FS) JEAN-FRANÇOIS ETTER,* MANFRED MAX BERGMAN, and THOMAS V. PERNEGER* *University of Geneva; and University of Cambridge Abstract Smoking-cessation advice may be more effective and acceptable if it is based on strategies used by people who quit smoking on their own. The objective of this study was to identify these self-change strategies and to develop and validate questionnaires measuring the frequency of their use in current and former smokers. Development of questionnaire items was based on qualitative data provided by 120 current and former smokers, and the validation study was conducted by mail in 638 smokers and ex-smokers in Geneva, Switzerland, from 1996 to We identified 5 distinct and interpretable self-change strategies in current smokers and 5 strategies in former smokers, and measured their frequency of use with a 19-item questionnaire in current smoker (SCS-CS) and with a 17 item questionnaire in former smokers (SCS-FS). Eight items and 2 strategies were common to both current and former smokers. the scales fulfilled criteria of test-retest reliability, and content, construct, and predictive validity. Participants who quit smoking between the baseline survey and the 1-month follow-up had higher baseline scores for all self-change strategies ( 0.65 to 1.16 standard deviation units) than participants who remained smokers at follow-up. These scales may be used to describe and understand the processes of smoking cessation and relapse, as well as to produce input data for computer systems which produce individually-tailored smoking cessation advice Elsevier Science Ltd. Key Words. Smoking-cessation, Psychometric-scales, Validity. Most ex-smokers have quit smoking by themselves, without professional help (United States Department of Health and Human Services, 1989). Understanding how former smokers managed to quit smoking and to avoid relapse may help in developing more effective smoking cessation interventions (Glynn, Boyd, & Gruman, 1990; Prochaska, DiClemente, & Norcross, 1992). A valid instrument assessing the use of self-change strategies is also needed to provide input data for computer systems that produce individually-tailored counseling reports for smokers and ex-smokers (Strecher et al., 1994; Velicer et al., 1993). Several studies analyzed strategies used by people who stopped smoking, but authors do not agree on the number and content of these strategies (Ahijevych & Wewers, 1992; Carey, Snel, Carey, & Richards, 1989; Glasgow, Klesges, Mizes, & Pechacek, 1985; Oei & Hallam, 1991; Pederson, Shelley, Ashley, & McDonald, 1996; Perri, 1985; Prochaska, Velicer, DiClemente, & Fava, 1988). Only one published instrument was submitted to comprehensive validation and replication studies, but the qualitative data used for the development of this questionnaire were collected in the United This research was supported by grants from the Swiss National Science Foundation to J.F. Etter ( , and ), by the Swiss Cancer League, the Swiss Federal Office of Public Health, Health Authorities of the Cantons of Geneva and Jura, the Geneva Cancer League, and the Swiss Foundation for Health Promotion. Requests for reprints should be sent to Jean-François Etter, Institute of Social and Preventive Medicine, University of Geneva, CMU, case postale, CH-1211 Geneva 4, Switzerland; etter@cmu.unige.ch 523

2 524 J.-F. ETTER et al. States over 20 years ago and the validation procedures were conducted in selected samples (DiClemente & Prochaska, 1982; Prochaska, DiClemente, Velicer, Ginpil, & Norcross, 1985; Prochaska et al., 1988). In addition, many items in this scale break recommended rules of items writing, such as simplicity, using only one idea per question, and avoiding the conditional tense. This, along with possible translation problems, probably explains why participants in pretests that we conducted in Geneva did not understand several items in a French-language translation of this scale. The present study aimed to identify the strategies used during self-initiated smoking cessation and to develop and validate a questionnaire measuring the frequency of use of these strategies in current and former smokers. METHODS Qualitative survey We used a systematic approach to scale development (Jackson, 1970; Streiner & Norman, 1995). We began by conducting a mail survey of current and former smokers to collect qualitative data on self-change strategies. Participants were recruited among persons who had already participated in previous smoking-related surveys (Etter, Perneger, & Ronchi, 1997), and were either members of the University of Geneva (students and staff) or residents of Geneva, Switzerland. The questionnaire was mailed once to 572 persons in December 1996, and 120 persons (21%) returned the questionnaire. A brief description of the five stages of change was presented (precontemplation, contemplation, preparation, action and maintenance) (Prochaska et al., 1992), followed by four questions on the activities, thoughts, and events that were used or occurred in each of the transitions between successive stages. Answers were classified according to their content in categories corresponding to the processes of change identified by Prochaska et al. (1988). Item development Based on these qualitative data and on theory, we wrote 210 items, following recommend rules for item writing (Streiner & Norman, 1995). These items were iteratively field-tested and improved in face-to-face interviews with 23 smokers and exsmokers recruited in cafés and restaurants in Geneva during daytime. Items that were not understood or not acceptable to participants were rewritten or rejected. When items were variations on the same idea, participants indicated which item they preferred. We retained only a limited number of items per content category and at the end of pretests, the list was reduced to 94 items. Use of different items in smokers and ex-smokers Stopping smoking and avoiding relapse after a quit attempt are distinct objectives that are reached using distinct strategies (Seidman & Covey, 1999). This point was clearly confirmed by the analysis of qualitative data and during face-to-face pretests with smokers and ex-smokers. Thus we decided to measure the frequency of use of self-strategies with different scales in current and former smokers. The 94-item questionnaire included 59 items directed at both current and former smokers, 27 items for current smokers only, and 8 items for former smokers only. Quantitative phase A second mail survey was conducted to test the properties of these 94 items, to identify underlying components, and to construct and validate a shorter composite scale.

3 Self-change strategies 525 Items were listed in random order under the following heading: Please indicate how often you currently engage in the following activities or think about the following things. Answers were given on a Likert-type scale with 5 response options ranging from Never (coded 1) to All the time (coded 5). Data collection. A random sample of 1,500 persons aged was drawn from the official file of Geneva residents. The survey was mailed to potential participants in 1997 and nonrespondents received a reminder postcard and two reminder questionnaires. The cover letter indicated that participation was limited to current smokers and to former smokers who quit smoking within the past 2 years. Longer-term exsmokers were excluded because they were not presumed to be actively involved in behavior change anymore. Non-smokers and smokers who did not wish to participate were asked to transmit the questionnaire to any current or former smoker they knew. No reward or payment were offered to participants. In addition to self-change strategies, questions covered the stages of change for smoking (Prochaska et al., 1992), attempts to quit smoking in the past 12 months, age, sex, the date when the questionnaire was filled and, among smokers, the number of cigarettes per day. Finally, the questionnaire included a short-form of Marlowe and Crowne s social desirability scale (MCSD; Reynolds, 1982). Follow-up. Participants who agreed to participate in a follow-up received the same questionnaire a second time, 1 month later, and a third brief questionnaire 1 year later. The first follow-up survey was answered on average 36 days after the baseline survey, by 151 persons (115 smokers and 36 ex-smokers, 24% of the baseline sample). The second follow-up survey was answered on average 403 days (13 months) after the baseline survey, by 185 persons (148 smokers and 37 ex-smokers, 29% of the baseline sample). Psychometric properties The following tests were performed to assess the characteristics of items and scales: Distributions. We examined whether items and composite scales produced variability, acceptable floor and ceiling effects, and few missing data. Factorial structure. We used factor analysis to identify underlying components. The number of factors to retain was determined by criteria of interpretability and content validity, as well as by Velicer s Minimum Average Partial (MAP) test and Horn s parallel analysis (Gorsuch, 1991; Horn, 1965; Velicer, 1976). These analyses were conducted separately in current and in former smokers. The principal components method with Varimax rotation was used. Stability of the factorial structure. To assess the robustness of the component structure, we performed factor analysis separately in men and in women. Confirmatory factor analysis. We used confirmatory factor analysis to assess whether our component solution adequately fit the data. Alternative models presuming the existence of one to eight factors were compared with the Adjusted Goodness of Fit Index (AGFI; Jöreskog & Sörbom, 1989), the Normed Fit Index (NFI; Bentler & Bonett, 1980) and the Comparative Fit Index (CFI; Bollen, 1989).

4 526 J.-F. ETTER et al. Item-scale correlations. We computed item-scale partial correlations, that is, correlations of each item with its subscale excluding this item. Internal consistency. We tested whether the composite scales reached the recommended criterion of coefficient alpha 0.7 (Nunnally & Bernstein, 1994). Test-retest reliability. Test-retest reliability was assessed using baseline and 1-month follow-up data. We computed test-retest intraclass correlation coefficients for all items and composite scales (Streiner & Norman, 1995). The frequency of use of self-change strategies may change considerably over time, in particular when people move from one stage of change to the next. Thus test-retest correlations were assessed only in the 120 persons who were in the same stage of change in both test and retest. Content validity. Content validity describes the capacity of a questionnaire to represent adequately the concept under investigation. The content of the final scales was compared with categories of answers in qualitative data and with published data. Construct validity We tested the following hypotheses about the associations between self-change strategies and external variables (Streiner & Norman, 1995). Association with the stages of change. Published data show that self-change strategies are used differently in the various stages of change (Ahijevych & Wewers, 1992; DiClemente & Prochaska, 1985; Kristeller, Rossi, Ockene, Goldberg, & Prochaska, 1992; Perz, DiClemente, & Carbonari, 1996; Pollak, Carbonari, DiClemente, Niemann, & Mullen, 1998; Prochaska & DiClemente, 1983; Prochaska, Velicer, DiClemente, Guadagnoli, & Rossi, 1991). Even though results of these studies are not congruent (Sutton, 1996), we hypothesized that the frequency of use of self-change strategies would increase progressively from precontemplation to contemplation and preparation, and that self-change strategies would be used more frequently in the action than in the maintenance stage of change. Quit attempts in past year. Because smokers who attempted to quit smoking recently are likely to be more actively involved in behavior change than those who did not attempt to quit, we hypothesized that self-change strategies would be more frequently used by current smokers who attempted to quit smoking in the past 12 months than by those who did not. Predictive validity. We hypothesized that a high frequency of use of self-change strategies at baseline would predict smoking cessation at both follow-ups (1 month and 13 months) in baseline smokers, and maintenance of abstinence in ex-smokers. Association with social desirability. Avoiding a social desirability bias is important in smoking-related questionnaires, since smoking is increasingly a socially undesirable behavior. We computed correlations between individual items and composite scales with the social desirability score. Translation into English We conducted a rigorous translation procedure to provide English-speaking clinicians and researchers with a valid translation of the questionnaire. First three indepen-

5 Self-change strategies 527 dent translations were made by two authors (JFE and TP, who are trained and experienced in survey methodology and smoking prevention) and by a professional translator whose mother tongue was English. Then, a synthesis of these three translations was tested and iteratively improved in smokers and ex-smokers whose mother tongue was English, recruited through the Internet. First, 30 persons suggested alternative formulations to the translated items. Then three to five alternative formulations were presented for each item, and 28 persons voted for the best formulation of each item. the most frequently chosen formulations were included in the final version of the scales (Tables 1 and 2). RESULTS Qualitative survey The 120 participants in the qualitative survey were on average 34 years old, 68% were women, and 68% were current smokers. Participants wrote 710 interpretable statements on activities, thoughts, and events that are used or occur in the transitions between the various stages of change (Table 3). All statements were attributed to one of the processes of change identified by Prochaska, and to an additional category called Events that cause change. These statements formed the basis of the 94-item questionnaire used in the quantitative survey (see Methods). Table 1. Self-change strategies in current smokers (SCS-CS) and loadings from factor analysis Factors Dimensions and items, in current smokers Commitment to change 1 I tell myself that I should stop smoking 79 2 I tell myself that I am tired of being addicted to cigarettes 74 3 I tell myself that I would be more physically fit if I stopped smoking I think about the benefits of giving up smoking Taking control 5 I try to spend a whole evening without smoking 81 6 In public places, I sit in the NO-smoking sections 72 7 After meals, I keep myself busy rather than smoke 71 8 To avoid the temptation to smoke, I stay away from places where people smoke 67 9 I wait as long as I can before I light my first cigarette for the day Risk assessment 10 I tell myself that smoking will shorten my life I am afraid that smoking will give me lung cancer I think about the effects of smoking on my lungs The information on the risks of smoking gives me something to think about Helping relationships 14 I tell others about my effort to quit smoking I tell others about my intention to quit smoking I ask friends and family for support to help me quit smoking 63 Coping with temptation to smoke 17 To deal with my craving for cigarettes, I concentrate on other things I keep busy to overcome the urge to smoke I take deep breaths to fight off the desire to smoke 73 Loadings are multiplied by 100. Loadings 30 are not shown. The questionnaire heading reads: Please indicate how often you currently engage in the following activities or think about the following things. Response options are: never, sometimes, fairly often, very often, all the time.

6 528 J.-F. ETTER et al. Table 2. Self-change strategies in former smokers (SCS-FS) and loadings from factor analysis Factors Dimensions and items, in former smokers Risk assessment 1 The thought of the diseases caused by smoking scares me 77 2 I am afraid that smoking will give me lung cancer 77 3 I think about the disadvantages of smoking 73 4 The information on the risks of smoking gives me something to think about 67 Coping with temptation to smoke 5 To deal with my craving for cigarettes, I concentrate on other things 84 6 I keep busy to overcome the urge to smoke 82 7 I take deep breaths to fight off the desire to smoke 74 Stimulus control 8 To avoid the temptation to smoke, I stay away from places were people smoke 76 9 In public places, I sit in the no-smoking sections I ask other people not to smoke in my home I avoid situations which make me want to smoke Self reevaluation 12 I am proud to have quit smoking I feel a sense of accomplishment in having stopped smoking I feel stronger than those who continue to smoke 69 Commitment to maintain change 15 I promise myself not to smoke ever again I tell others about my effort to quit smoking I think about ways of overcoming the urge to smoke Loadings are multiplied by 100. Loadings 30 are not shown. The questionnaire heading reads: Please indicate how often you currently engage in the following activities or think about the following things. Response options are: never, sometimes, fairly often, very often, all the time. One third (31%, n 217) of statements belonged to the category labelled Consciousness raising, which covered the awareness of risks and other negative consequences of smoking. Most of these statements (n 121) concerned the transition between precontemplation and contemplation (Table 3). One fifth (19%, n 37) of all statements were classified in the category labelled Self-reevaluation, which covered the pride of having quit smoking and the guilt of being a smoker. Most of these statements concerned the transition between the Action and Maintenance stages. About 10% (n 70) of the statements covered events that elicit smoking cessation, such as a smoking-related illness in oneself or in a relative, or a pregnancy. Quantitative survey A total of 638 valid questionnaires were returned (43% of the questionnaires initially mailed). Participants were on average 39 years old and 45% were men. Fortyfour percent of participants were in the precontemplation stage of change (n 281), 23% in contemplation (n 149), 5% in preparation (n 33), 8% in action (n 53) and 10% in maintenance (n 63). The stage of change could not be identified in 9% of participants (n 59). On average, smokers smoked 18 cigarettes per day. Selection of items and subscales First, we eliminated 19 items that had important floor or ceiling effects, low test-retest correlations, or a low communality in a preliminary factor analysis. We compared items that were variations of a same idea and eliminated items that had the worse characteristics. Then, we performed two separate factor analyses on the remaining 67 items (in smokers)

7 Self-change strategies 529 Table 3. Activities and thoughts used during the transitions between five stages of behavior change for smoking cessation, from qualitative data A B C D Total Consciousness raising Increased awareness of the negative consequences of smoking (health, dependence on nicotine, physical fitness, bad breath, bad smell, costs, and responsibility towards children). Increased awareness of the positive aspects of quitting (well-being, quality of life). Read articles, statistics, TV, radio. Look for information on risks how to quit. Self-reevaluation Pride of having quit smoking. Improved self-confidence and self-image after quitting. Shame or culpability of being a smoker. Counter conditioning Do something else instead of smoking. Eat. Relax. Engage in sport/exercise. Stimulus control Avoid tempting situations, decrease the number of cigarettes per day, delay the first cigarette of the day, avoid to buy or carry cigarettes. Self-liberation Increased motivation. Willpower. Optimism. Set a quit date. Plan quit attempt. Helping relationships Speak of quitting smoking with relatives, with physician. Tell relatives that one is going to quit. Corrective emotional experience Fear of smoking-related diseases Social liberation, social pressure Criticism from spouse, relatives, colleagues. Awareness of the increasing number of ex-smokers. Working in a nonsmoking workplace. Reinforcement management Congratulate oneself, being congratulated by others, buy oneself gifts. Environmental reevaluation Cigarette butts everywhere, dirt, bad smell in apartment, bothering others, pollution. Use of substances and devices (Nicotine patch or gum, filters) Significant events Bronchitis, persistent cough, infarction, cancer, smoking-related death or illness of a relative, pregnancy or intention to have a child. Total number of citations A change from precontemplation to contemplation, B contemplation to preparation, C preparation to action, D action to maintenance. and 48 items (in ex-smokers). A five factor solution appeared appropriate in both groups. Progressively, we reduced the data set to 19 items in smokers and 17 items in ex-smokers (including 8 items common to both smokers and ex-smokers; see Appendix A), eliminating items with low test-retest correlations and with low loadings in factor analysis. These five factors explained 66% of total variance, both in current and in former smokers. Items were attributed to subscales according to their loadings in factor analysis and added to form composite scores. Scores were standardized to mean 0 and standard deviation 1. The two scales were called Self-Change Strategies for Current Smokers (SCS-CS) and Self-Change Strategies for Former Smokers (SCS-FS) (Tables 1 and 2). Self-change strategies in current smokers. The first strategy, Commitment to change, included items on taking the decision to quit smoking and on reassessing the advan-

8 530 J.-F. ETTER et al. tages of quitting. The second strategy, Taking control, included items on taking steps to control one s habit (such as spending a whole evening without smoking) and on avoiding smoking-related situations. The third strategy, Risk assessment contained items on thinking about the impact of smoking on health. The fourth strategy was Helping relationships and the fifth was Coping with the temptation to smoke. Self-change strategies in former smokers. The first strategy was labelled Risk assessment and the second Commitment to maintain change. The item I tell people around me about my efforts to stop smoking had the highest loading on the latter factor but, in current smokers, this item was attributed to Helping relationships. This discrepancy seemed acceptable since this item may reflect both a public commitment to abstinence and a call for help. The third strategy was Coping with temptation to smoke and included the same items as in current smokers. The fourth strategy, Self-reevaluation, was specific to exsmokers and included items on positive thoughts about having quit smoking. The fifth strategy, Stimulus control, included items on avoiding exposure to smoking stimuli. Robustness of the factorial structure In current smokers, the same factorial structure was found in the whole sample and when the data were analyzed separately in men (n 227), and in women (n 295). In ex-smokers, the same factorial structure was found in the whole sample and in women (n 58). In men (n 57), all items but one (Item No. 13) loaded on the expected factor. The latter discrepancy may be due to the small sample size used in this analysis. Confirmatory factor analysis In both current and former smokers, each successive model, starting from a one factor model to a five factor model, showed substantial improvement in goodness-of-fit indices over the earlier model (Table 4). From model 5 to model 8, goodness-of-fit indices reached a plateau. Thus five-factor models were preferred in both current and former smokers, since they did as well as models with more factors but were more parsimonious. In both current and former smokers, goodness-of-fit indices were lower than the recommended 0.95 cutoff values (Jöreskog & Sörbom, 1989; Bentler & Bonett, 1980). Age and sex differences In current smokers, men used three of the five strategies less frequently than women (Risk Assessment, Taking Control, and Coping with Temptation to Smoke). Table 4. Fit indices for alternative factor models of self-change strategies, in current and former smokers 1 Factor 2 Factors 3 Factors 4 Factors 5 Factors 6 Factors 7 Factors 8 Factors In smokers AGFI NFI CFI In ex-smokers AGFI NFI CFI AGFI Adjusted Goodness of Fit Index (Jöreskog & Sörbom, 1989); NFI Normed Fit Index (Bentler & Bonett, 1980); CFI Comparative Fit Index (Bollen, 1989).

9 Self-change strategies 531 These statistically significant differences raged between 0.18 and 0.28 standard deviation units. In former smokers, no difference in self-change strategies was found between men and women. Age was not associated with use of self-change strategies. Characteristics of items and scales Distributions of answers. All items and composite scales had low proportions of missing answers and no ceiling effects, but several items had important floor effects (Tables 5 and 6). Reliability Even though the scales contained only 3 to 5 items, all internal consistency coefficients exceeded the criterion of alpha 0.7. Test-retest reliability coefficients ranged from 0.59 to 0.86 for composite scales and were acceptable for all individual items. Item-scale partial correlations were acceptable for all items (Tables 5 and 6). Content validity All main categories of qualitative data were represented in the final questionnaire (Table 3). Construct validity Association with the stages of change. In current smokers, all strategies were increasingly used in more advanced stages. Differences between the precontemplation and preparation stages ranged from 0.59 to 1.58 standard deviation units (Table 5). These associations remained statistically significant after adjustment for the number of cigarettes per day. No difference in the frequency of use of self-change strategies was found between ex-smokers in the action and maintenance stages. Quit attempts in the past year. All self-change strategies, either measured by individual items or by composite scores, were more frequently used by smokers who had attempted to quit smoking during the past year than by smokers who had not. These associations remained statistically significant after adjustment for the number of cigarettes per day. Predictive validity. The 7 participants who quit smoking between the baseline survey and the 1-month follow-up had higher baseline scores for all self-change strategies than participants who remained smokers, these differences were statistically significant for four of five strategies (Table 5). Among baseline smokers, the frequency of use of self-change strategies was not predictive of quitting smoking at 13-month follow-up. No baseline ex-smoker had relapsed at 1-month follow-up, but 7 had relapsed to daily smoking at 13-month follow-up. At baseline, relapsers used the Stimulus control strategy more often than ex-smokers who maintained abstinence (difference 0.94 standard deviation units, p 0.004). Social desirability. No composite scale was significantly associated with the social desirability score (correlations ranged from to 0.17). Four items were significantly correlated with this score, but correlations were low ( 0.2).

10 532 J.-F. ETTER et al. Table 5. Item and scale characteristics, in current smokers Floor % Ceiling % Missing % Item-scale correlation or Cronbach Test-retest correlation Precont./ Contempl./ Quit attempt contempl. a prepar. a in past year a Quit smoking at 1-month follow-up a Abbreviated item content I should stop smoking *** 0.36* 0.47*** 0.93* Enough with dependence *** 0.51** 0.43*** 0.62 Physical fitness *** 0.36* 0.38*** 0.50 Benefits giving up *** 0.40* 0.49*** 0.78* Evening not smoking ns 0.84*** 0.67*** 0.66 Sit in nonsmoking area ns 0.38* 0.43*** 0.65 After the meal ns 0.95*** 0.48*** 0.09 Avoid places *** 0.46* 0.48*** 0.91** Delay first cigarette ns 0.45* 0.66*** 0.30 Shorten my life *** 0.02 ns 0.03 ns 1.38** Effect on lungs *** 0.28 ns 0.39*** 1.28** Frightened lung cancer *** 0.10 ns 0.22** 1.04** Information risks *** 0.35 ns 0.34*** 0.38 Tell about my efforts *** 0.29 ns 0.42*** 1.17** Tell about intention *** 0.54* 0.53*** 1.10* Ask for help *** 0.38 ns 0.48*** 0.45 Concentrate stg. else *** 0.06 ns 0.29*** 0.51 Undertake other activ *** 0.13 ns 0.42*** 0.29 Take deep breaths *** 0.26 ns 0.27** 0.81 Scales Commitment to change *** 0.49** 0.55*** 0.98** Taking control ** 0.80*** 0.74*** 0.92** Risk assessment *** *** 1.08** Helping relationships *** 0.50* 0.60*** 1.16** Coping with temptation *** *** 0.65 a Difference between groups expressed in standard deviation units of strategies scores. *p 0.05; **p 0.01; ***p

11 Self-change strategies 533 Table 6. Item and scale characteristics, in former smokers Floor % Ceiling % Missing % Item-scale correlation or Cronbach Test-retest correlation Action/ Maint a Abbreviated item content Afraid of lung cancer Descriptions of illness Disadvantages of smoking Information on risks I concentrate on other things I undertake some other activity I take some deep breaths * I tell people around me about my efforts Ways of overcoming the need to smoke I promise myself not to smoke again I am proud to have succeeded I feel a sense of accomplishment Stronger than those who continue to smoke I stay away from places where people smoke I sit in the NO-smoking area I ask other people not to smoke in my home I avoid situations Scales Risk assessment Coping with temptation to smoke Commitment to maintain change Self reevaluation Stimulus control a Difference between groups expressed in standard deviation units of strategies scores. *p DISCUSSION In this study, we identified eight distinct and interpretable self-change strategies that smokers and ex-smokers use to progress from the stage where they have no intention to quit smoking to the long-term maintenance of abstinence. Furthermore, we developed and validated two scales (SCS-CS and SCS-FS) measuring the frequency of use of these strategies in current and former smokers. The identification of these selfchange strategies and the development of scales to measure them will be useful principally for interactive computer systems which produce individually tailored feedback letters to smokers and ex-smokers (e.g., These scales are also valuable tools for researchers who analyze how smokers progress through the stages of change, quit smoking, and maintain abstinence. Content of the scales The instrument was developed from qualitative data collected in a large sample of smokers and ex-smokers. This sample size enabled us to count citations made by participants and to assess the relative importance of each strategy. All the main categories identified in qualitative data were represented in the final scale. Thus SCS-CS and SCS-FS scales have demonstrable content validity.

12 534 J.-F. ETTER et al. The scales measure the frequency of use of five self-change strategies in smokers (19 items) and five strategies in ex-smokers (17 items); eight items and two strategies are common to both current and former smokers. Risk assessment was present in both current and former smokers and formed the most frequent category of qualitative data, which underlines the importance of this strategy in the process of smoking cessation. Making a commitment to change (in smokers) or to maintain change (in ex-smokers) seems to be the next step that smokers and ex-smokers take in this process. Taking control and Stimulus control covered actions that smokers and ex-smokers take to control their smoking and to avoid smoking stimuli. Coping with the temptation to smoke covers distracting activities that enable smokers and ex-smokers to face the urge to smoke. Helping relationships is specific to current smokers and appears to be critical in the transition from the Preparation to the Action stages of change (Table 3). A positive Self-reevaluation seemed important to maintain abstinence among ex-smokers. Comparison with a previously published scale Qualitative data, face-to-face interviews and theoretical considerations led us to conclude that self-change strategies should be measured with different scales in current and former smokers. This is an important difference with existing questionnaires (Prochaska et al., 1988), but is necessary if we consider that quitting smoking and maintaining abstinence are distinct problems (Seidman & Covey, 1999). Our data, as well as data on self-change strategies used by methadone and heroin users concur to suggest that there may be fewer than 10 distinct self-change strategies (Belding, Iguchi, Lamb, Lakin, & Terry, 1995; Tejero, Trujols, Hernandez, Perez de los Cobos, & Casas, 1997 (Table 7). In particular, the strategy called Social liberation was not identified in these different studies. Consciousness raising, Dramatic relief, and Environmental reevaluation appeared to form a single process covering an assessment of the risks and disadvantages of smoking. Differences between our results and published data can arise from differences in the cultural context in which these studies were conducted, from differences in the behaviors under study or from differences in the methods used. Table 7. Comparison of scales assessing self-change strategies and processes of change Prochaska, Velicer, DiClemente, & Fava (1988) Smokers and ex-smokers, 10 processes Belding, Iguchi, Lamb, Lakin, & Terry (1995) Methadone users, 4 processes SCS-CS Current smokers, 5 strategies SCS-FS Former smokers, 5 strategies Consciousness raising and Reevaluation Risk assessment Risk assessment dramatic relief Self liberation Self liberation Commitment to change Commitment to maintain change Stimulus control Behavioral processes Taking control Stimulus control Counter conditioning Behavioral processes Coping with tempation to smoke Coping with temptation to smoke Helping relationships Reinforcing relations Helping relationships Self-reevaluation Reevaluation Self-reevaluation Environmental Reevaluation reevaluation Reinforcement Reinforcing relationships management Social liberation Note. SCS-CS self-change strategies in current smokers; SCS-FS self-change strategies in former smokers.

13 Self-change strategies 535 Even though the specifics of our results differ somewhat from published data, this study globally supports the validity of Prochaska s Transtheoretical Model of Change. First, almost all statements written by participants in the qualitative survey could be classified in the 10 processes of change identified in this model. Second, the content of our self-change strategies was close to the content of Prochaska s processes of change. More importantly, our data confirmed that use of self-change strategies is strongly associated with stages of change, which provides an additional argument in favor of matching smoking cessation advice with the stage of each participant (Farkas et al., 1996; Prochaska & Velicer, 1996). Validity tests The scales fulfilled criteria of test-retest reliability, content-, construct- and predictive validity, and were not biased by social desirability. Confirmatory factor analyses showed that five-factor models adequately represented the data, even thought goodness-of-fit indices were lower than hoped for, either because the sample size in exsmokers was to small, because several variables loaded on more than one factor, or because of inadequate model specification. An important argument in favor of the validity of the SCS-CS scale is its ability to predict smoking cessation after one month in baseline smokers. The scale did not predict smoking cessation at 13 months, perhaps because the use of self-change strategies changes over time, and therefore predicts smoking cessation better over the shortterm than over the long-term, The predictive validity of this scale is also an argument supporting the identification and measurement of self-change strategies, which has been criticized (Sutton, 1996). In ex-smokers, a frequent use of Stimulus Control was predictive of relapse, which probably means that ex-smokers avoid high-risk situations because they lack confidence in their ability to resist smoking in these situations. A low self-efficacy, rather than the use of Stimulus Control per se, is probably the key predictor of relapse (e.g., Yates & Thain, 1985). Relatively important floor effects were observed for several items. This may correspond to reality. Most smokers remain in the same stage of change for long periods, and most persons who quit smoking relapse in the following year (Curry & McBride, 1994; Fitzgerald & Prochaska, 1990). This suggests that most smokers and ex-smokers do not make a regular use of self-change strategies. An interesting result of our qualitative survey is the identification of specific events that motivate change, in particular from the precontemplation to the contemplation stages of change. This result can be of help to clinicians, since it suggests that patients will be more receptive to smoking cessation advice when one of these events happens to them (e.g., smoking-attributable illness in oneself or in a relative, pregnancy or intention to become pregnant, etc.). Limitations of this study A first limitation of this study was the relatively small number of ex-smokers in our sample, which probably explains why we detected no statistically significant difference in the use of self-change strategies between ex-smokers in the action and maintenance stages of change. The validation of SCS-FS will need assessment in larger samples of ex-smokers. Furthermore, replication of results in different populations is necessary to complete the validation of the scales. Only 21% of the original sample responded (318 of 1500), from a population where the prevalence of smoking is 32% (World Health

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16 538 J.-F. ETTER et al. Appendix A: Questionnaire sur les stratégies de changement chez les fumeurs et les ex-fumeurs Dimensions et questions, chez les fumeurs Evaluation du risque Je me dis que je vivrai moins longtemps parce que je fume J ai peur que la cigarette provoque chez moi un cancer du poumon Je pense aux conséquences du tabagisme sur mes poumons Je réfléchis aux informations sur les dangers de la cigarette Engagement à changer Je me dis que je devrais arrêter de fumer Je me dis que j en ai assez de dépendre des cigarettes Je me dis que si j arrêtais de fumer, je serais en meilleure forme Je réfléchis aux avantages d arrêter de fumer Prise de contrôle J essaie de passer une soirée entière sans fumer Dans les lieux publics, je m installe dans la zone NON-fumeurs Après le repas, je m occupe à autre chose plutôt que de fumer Pour ne pas être tenté de fumer, j évite les endroits où l on fume J essaie de retarder le plus possible la première cigarette de la journée Aide des autres Je parle autour de moi de mes efforts pour arrêter de fumer Je parle autour de moi de mon intention d arrêter de fumer Je demande à mes proches de soutenir mes efforts pour arrêter de fumer Résister à l envie de fumer Pour résister à l envie de fumer, je me concentre sur autre chose Pour résister à l envie de fumer, j entreprends une autre activité Pour faire passer l envie de fumer, j effectue quelques respirations profondes Dimensions et questions, chez les ex-fumeurs Evaluation du risque Les descriptions des maladies causées par la cigarette m impressionnent J ai peur que la cigarette provoque chez moi un cancer du poumon Je réfléchis aux inconvénients de la cigarette Je réfléchis aux informations sur les dangers de la cigarette Engagement à maintenir le changement Je me fais à moi-même la promesse de ne plus fumer Je parle autour de moi de mes efforts pour arrêter de fumer Je réfléchis aux moyens de résister à l envie de fumer Contrôle des stimuli Pour ne pas être tenté de fumer, j évite les endroits où l on fume Dans les lieux publics, je m installe dans la zone NON-fumeurs Je demande aux autres de ne pas fumer dans mon appartement J évite les situations qui me donnent envie de fumer Réévaluation de soi-même Je suis fier d avoir réussi à arrêter de fumer Je ressens la satisfaction d avoir remporté une victoire parce que j ai arrêté de fumer Je me sens plus fort(e) que ceux qui continuent à fumer Résister à l envie de fumer Pour résister à l envie de fumer, je me concentre sur autre chose Pour résister à l envie de fumer, j entreprends une autre activité Pour faire passer l envie de fumer, j effectue quelques respirations profondes En-tête: Indiquez à quelle fréquence vous pratiquez les activités suivantes ou pensez aux choses suivantes, actuellement. Réponses: Jamais 1, Quelquefois 2, Assez souvent 3, Très souvent 4, Tout le temps 5.