Smoking Self-Efficacy Scales

Abstract

The Smoking Self-Efficacy Scales (SSES), developed primarily by Carlo C. DiClemente, James O. Prochaska, Wayne F. Velicer, and colleagues within the Transtheoretical Model of Behavior Change (TTM), represent one of the most widely utilized and psychometrically validated measurement batteries in addictive behavior research. Grounded in Albert Bandura‘s social cognitive theory and contextualized within the stages of change, the SSES assesses an individual’s situational confidence in their ability to refrain from smoking when facing high-risk relapse contexts. The instrument exists primarily in a full 20-item version and an abbreviated 9-item short form, capturing three robust, replicable, and theoretically coherent first-order dimensions: Negative Affect, Social/Positive situations, and Habitual/Craving (or Habit/Addictive) circumstances.

Respondents evaluate their confidence utilizing a fully anchored 5-point Likert-type scale ranging from 1 (Not at all confident) to 5 (Extremely confident). Decades of psychometric evaluation across diverse international cohorts, community samples, and clinical smoking cessation trials demonstrate exceptional internal consistency reliability, with Cronbach’s alpha coefficients routinely exceeding .90 across subscales (specifically reported as .95 for Negative Affect, .93 for Social/Positive, and .92 for Habit/Addictive in landmark validation literature). Confirmatory factor analyses consistently substantiate both correlated three-factor and second-order hierarchical configurations. Furthermore, the scales exhibit robust construct, predictive, and discriminant validity, dynamically tracking an individual’s progression from Precontemplation through Maintenance, predicting short- and long-term point-prevalence abstinence, and delineating distinct relapse vulnerability profiles. This comprehensive review examines the conceptual origins, structural properties, psychometric benchmarks, scoring protocols, and empirical applications of the Smoking Self-Efficacy Scales in contemporary behavioral science and clinical practice.

Keywords

Smoking Self-Efficacy Scales, SSES, Transtheoretical Model, Nicotine Dependence, Smoking Cessation, Self-Efficacy, Relapse Prevention, Negative Affect, Situational Confidence, Psychometrics

Authors

The theoretical conceptualization and empirical operationalization of the Smoking Self-Efficacy Scales are credited to a distinguished cadre of clinical psychologists and quantitative psychometricians who pioneered the integration of social-cognitive constructs into addiction science:

• Carlo C. DiClemente, Ph.D.: Emeritus Professor of Psychology at the University of Maryland, Baltimore County (UMBC Habits Lab). Co-originator of the Transtheoretical Model of Behavior Change, Dr. DiClemente led the initial investigations translating Bandurian self-efficacy to self-change and structured cessation across smoking populations.
• James O. Prochaska, Ph.D. (1942–2023): Formerly Professor of Clinical and Health Psychology and Director of the Cancer Prevention Research Center at the University of Rhode Island. Co-developer of the TTM, Dr. Prochaska synthesized the stages and processes of change with cognitive mediators of behavioral maintenance.
• Wayne F. Velicer, Ph.D. (1944–2017): Formerly Professor of Psychology and Co-Director of the Cancer Prevention Research Center at the University of Rhode Island. An internationally recognized quantitative methodologist and psychometrician, Dr. Velicer spearheaded the structural equation modeling, exploratory and confirmatory factor analyses, and structural invariant modeling that validated the 20-item and short-form inventories.
• Michael Gibertini, Ph.D.: Clinical psychologist and researcher who collaborated closely on the seminal 1985 empirical investigations linking stage-specific transitions to situational self-efficacy appraisal.
• Joseph S. Rossi, Ph.D.: Professor of Psychology and Director of the Cancer Prevention Research Center at the University of Rhode Island, who contributed extensively to the structural integration of temptation and self-efficacy constructs across population-level behavioral health initiatives.

Purpose

The primary purpose of the Smoking Self-Efficacy Scales (SSES) is to systematically evaluate an individual’s perceived capability to resist the urge to smoke across a spectrum of specific, high-risk environmental, emotional, and physiological situations. In addiction literature, tobacco dependence is recognized not merely as a neurochemical addiction to nicotine, but as a complex behavioral repertaire sustained by conditioned cues, classical conditioning, operant reinforcement, and cognitive expectancies. Consequently, standard physiological measures of dependence (such as the Fagerström Test for Nicotine Dependence [FTND] or expired carbon monoxide) capture only physical tolerance and consumption patterns, failing to index the psychological self-regulatory capacities necessary to initiate and maintain abstinence.

The SSES bridges this diagnostic gap by operationalizing self-efficacy as a multidimensional, state-like cognitive mediator rather than a static personality trait. Clinically, the scale accomplishes several critical functions:

• Stage Diagnosis and Readiness Profiling: Within the Transtheoretical Model, self-efficacy demonstrates a predictable non-linear trajectory across the stages of change. In Precontemplation and Contemplation, confidence to resist smoking is exceptionally low, whereas temptation is high. Self-efficacy increases sharply during the Preparation stage, accelerating through Action, and reaching its zenith during Maintenance. Administering the SSES allows clinicians to determine whether a client possesses sufficient self-regulatory confidence to set an imminent quit date.
• Targeted Relapse Prevention Planning: Grounded in G. Alan Marlatt‘s cognitive-behavioral relapse model, the SSES identifies specific situational deficits. A patient may display very high confidence in resisting cigarettes during social gatherings (Social/Positive subscale) but exhibit profound vulnerability when confronted with interpersonal conflict or distress (Negative Affect subscale). By pinpointing these idiosyncratic vulnerabilities, clinicians can tailor cognitive restructuring, behavioral substitution, distress tolerance training, and stimulus control strategies to the exact domains of highest risk.
• Treatment Outcome Monitoring and Process Evaluation: Throughout clinical interventions (whether pharmacological, behavioral, or combined), serial administrations of the SSES provide an ongoing gauge of psychological recovery. Interventions that fail to bolster self-efficacy during early treatment often exhibit elevated relapse rates at 6- and 12-month follow-ups. A plateau or drop in self-efficacy frequently precedes a behavioral lapse or full relapse, enabling preemptive clinical intervention.
• Population Health and Tailored Interventions: In public health and digital intervention platforms, the 9-item short form provides a low-burden, psychometrically sound instrument for computer-tailored expert system communications, generating algorithmic feedback that reinforces behavioral change mechanisms across broad populations.

Psychological Construct

The psychological construct evaluated by the Smoking Self-Efficacy Scales is situational self-efficacy—specifically, the subjective conviction that one can successfully execute the behaviors required to maintain abstinence from tobacco across challenging internal and external settings. Albert Bandura conceptualized self-efficacy not as an omnibus self-esteem measure or general optimism, but as an explicit cognitive judgment regarding performance capabilities within specified behavioral domains. In the context of addictive behaviors, this manifests as “abstinence self-efficacy” or “resistance self-efficacy.”

Velicer, DiClemente, Prochaska, and colleagues established that temptation to smoke and confidence to abstain represent complementary, inverse, yet psychometrically distinguishable axes of relapse risk. While temptation measures the strength of the urge provoked by a cue, self-efficacy indexes the perceived strength of the executive self-regulatory system to override that urge. Extensive psychometric modeling has isolated three definitive situational dimensions underlying this construct:

1. Negative Affect / Emotional Distress

The Negative Affect dimension assesses an individual’s confidence in refraining from smoking when experiencing adverse, destabilizing internal emotional states. In tobacco dependence, nicotine is extensively utilized as a maladaptive affect-regulation mechanism; smoking serves to attenuate feelings of anxiety, depressive symptoms, frustration, rage, and interpersonal friction via rapid dopaminergic and noradrenergic neurotransmission. Situations comprising this construct include encountering unexpected crises (e.g., accidents, family bereavement), experiencing acute frustration when events do not unfold as planned, enduring familial arguments, or coping with severe anxiety, sadness, and stress.

Individuals scoring low on this dimension exhibit an absence of psychological coping mechanisms to decouple negative emotional arousal from the conditioned impulse to smoke. In clinical settings, low Negative Affect self-efficacy is the most robust and consistent psychological predictor of rapid, post-cessation lapse and relapse, representing the cognitive manifestation of affective vulnerability.

2. Social / Positive Situations

The Social / Positive dimension captures situational confidence when navigating environments characterized by high social facilitation, celebration, positive affect, and ambient smoking cues. Smoking is fundamentally a social behavior embedded in cultural rituals, interpersonal bonding, and celebratory milestones. Cues within this domain include attending parties with friends, having drinks at a bar or cocktail lounge, relaxing over coffee while conversing, celebrating achievements, and observing others smoking and visibly enjoying it.

In these scenarios, the cognitive challenge is not the alleviation of psychological distress, but resisting the hedonic pull of positive reinforcement, social modeling, and normative group pressure. Low self-efficacy in this subscale reflects susceptibility to social conditioning, perceived social isolation without tobacco, and an inability to maintain behavioral refusal skills in celebratory or alcohol-involved environments.

3. Habitual / Craving (Habit/Addictive) Scenarios

The Habitual / Craving dimension measures perceived confidence to withstand highly conditioned automatic behavioral routines, visceral cravings, and basic physiological urges. Over years of chronic nicotine administration, smoking becomes inextricably bound to diurnal biological cues and ingrained motor habits. This dimension indexes confidence when waking up in the morning facing a challenging day, experiencing an acute craving or intense desire for a cigarette, feeling the need for an energy lift, confronting the realization that quitting is an arduous task, or noticing that a substantial period has elapsed without a cigarette.

This construct reflects the intersection of classical neurobiological conditioning and conscious cognitive resistance. High scores on this subscale indicate an advanced capacity to tolerate physiological craving states, implement behavioral delays, and decouple automatic morning routines from the immediate behavioral reflex to smoke.

Theoretical Framework

The structural design and interpretive paradigm of the Smoking Self-Efficacy Scales are rooted at the theoretical crossroads of Bandura’s Social Cognitive Theory, the Transtheoretical Model of Behavior Change (Prochaska & DiClemente, 1983; Prochaska, DiClemente, & Norcross, 1992), and the Cognitive-Behavioral Model of Relapse Prevention (Marlatt & Gordon, 1985).

Bandura’s Cognitive Foundations

Bandura postulated that human behavior is motivated and regulated by ongoing reciprocal interactions among cognitive processes, environmental stimuli, and behavioral patterns. Central to this system are self-efficacy beliefs, which dictate:

• Whether a person will attempt to initiate behavioral modification;
• The magnitude of effort they will expend when obstacles arise; and
• Their perseverance and resilience when confronted with setbacks or high-risk cues.

According to Bandura, self-efficacy is constructed from four core informational inputs: mastery experiences (past personal successes), vicarious experiences (modeling observed in peers), verbal persuasion (encouragement from clinicians or support systems), and physiological/affective states (interpreting anxiety or craving not as inevitable failure, but as natural physiological feedback). The SSES operationalizes these tenets by measuring confidence across situations where these four informational streams converge to challenge self-mastery.

The Transtheoretical Model Integration

In the early 1980s, Prochaska and DiClemente integrated Bandura’s micro-level construct of self-efficacy into the macro-architecture of the Transtheoretical Model. The TTM posits that intentional behavioral change unfolds across five distinct stages:

1. Precontemplation: No intention to quit smoking within the foreseeable future (typically framed as within the next 6 months).
2. Contemplation: Aware that a problem exists and seriously considering quitting within the next 6 months, but ambivalent and not committed to immediate action.
3. Preparation: Intending to take action in the immediate future (usually within the next 30 days) and often having made an unsuccessful quit attempt in the past year.
4. Action: Explicit behavioral modification characterized by total cessation of smoking for less than 6 months.
5. Maintenance: Sustained continuous abstinence from smoking for 6 months to 5 years, during which relapse prevention is the central behavioral goal.

Within this framework, self-efficacy serves as a primary marker of stage progression. DiClemente et al. (1985) and Prochaska et al. (1988) demonstrated that self-efficacy operates as a crucial dynamic mediator: while decisional balance (pros and cons of smoking) shifts during Contemplation and Preparation, dramatic surges in situational self-efficacy are required to transition an individual from Preparation into Action, and to stabilize them in Maintenance. In longitudinal cohort modeling, the trajectory of self-efficacy reflects an inverse curvilinear relationship with perceived temptation; as individuals progress through Action into Maintenance, self-efficacy scores gradually ascend toward the maximum ceiling, while temptation scores progressively decline toward zero.

Validity

The psychometric validity of the Smoking Self-Efficacy Scales has been established across hundreds of empirical investigations encompassing clinical trials, epidemiological surveys, and cross-cultural adaptations.

Construct Validity

Construct validity is evidenced by the scale’s profound structural convergence with TTM theoretical predictions. In the seminal validation paper by DiClemente, Prochaska, and Gibertini (1985) involving 224 individuals engaged in self-change or structured cessation programs, mean self-efficacy scores showed highly significant, monotonic increases corresponding directly to the stage of change (F-tests significant at p < .001). Precontemplators and Contemplators exhibited uniformly depressed self-efficacy across all three domains, Preparation participants displayed moderate, emerging confidence, while individuals in the Maintenance stage demonstrated the highest self-efficacy scores.

Cross-sectional and longitudinal structural equation modeling conducted by Velicer et al. (1990) confirmed that the three-factor structure accounts for the vast majority of situational variance across distinct community populations (N > 1,000), proving that the construct validity holds across varying ages, socioeconomic groups, and historical levels of tobacco consumption.

Predictive and Criterion Validity

The SSES demonstrates extensive predictive validity regarding smoking cessation outcomes:

• Short-Term Relapse Prediction: Studies evaluating relapse following abrupt cessation demonstrate that individuals who return to smoking within 2 to 6 weeks possess significantly lower baseline and post-quit Negative Affect and Habitual/Craving self-efficacy scores compared to continuous quitters.
• Long-Term Maintenance: In prospective trials (Perz, DiClemente, & Carbonari, 1996), self-efficacy assessments collected at the end of active intervention significantly predicted continuous abstinence at 6-month, 12-month, and 24-month clinical endpoints. Higher baseline self-efficacy in social situations, coupled with rising negative-affect self-efficacy during treatment, predicted long-term success.
• Lapse-to-Relapse Progression: In Marlatt’s relapse prevention paradigm, experiencing an initial lapse (a single cigarette puff or slip) frequently triggers the Abstinence Violation Effect (AVE), culminating in a complete relapse. Research demonstrates that individuals with elevated baseline SSES scores are far more likely to contain a slip and reinstate complete abstinence rather than degenerating into an uncontrolled, regular smoking cycle.

Convergent and Discriminant Validity

Convergent validity is confirmed through significant correlations with validated addiction and affective instruments:

• Moderate-to-strong inverse correlations are observed with the Fagerström Test for Nicotine Dependence (FTND; r = -.35 to -.52), indicating that higher physical dependence predictably suppresses confidence to resist smoking, particularly in habitual/morning settings.
• Strong inverse correlations are recorded with cue-elicited craving measures and negative affect assessments, including the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI).
• Discriminant validity is supported by the SSES sharing only modest variance with generalized self-efficacy scales (e.g., the Schwarzer General Self-Efficacy Scale; r = .20 to .32) and global self-esteem measures, confirming Bandura’s assertion that domain-specific self-efficacy represents a distinct construct separable from global personality traits.

Reliability

The internal consistency and temporal stability of the Smoking Self-Efficacy Scales have been rigorously confirmed across decades of psychometric scrutiny:

Internal Consistency Reliability

In the seminal psychometric re-evaluation by Velicer, DiClemente, Rossi, and Prochaska (1990) involving both exploratory and confirmatory samples, the 20-item scale demonstrated world-class internal consistency across all primary subscales:

• Negative Affect: Cronbach’s alpha = .95
• Social/Positive: Cronbach’s alpha = .93
• Habitual/Craving (Habit/Addictive): Cronbach’s alpha = .92

Subsequent international validations (evaluating Spanish, French, Korean, Chinese, and German adaptations) report subscale alphas consistently hovering between .86 and .96. For the 9-item short form, internal consistency remains exceptionally robust despite the reduced item count per subscale, with subscale alphas routinely reported between .82 and .90, and full-scale composite reliability frequently reaching .91 to .94.

Test-Retest Stability

Because self-efficacy is theoretically conceptualized as a dynamic cognitive state responsive to therapeutic intervention and life events, test-retest reliability must be evaluated over brief intervals where clinical or environmental conditions remain stable. Across 2- to 3-week test-retest windows among non-treatment-seeking smokers (smokers in the Precontemplation stage), Pearson correlation coefficients (r) and Intraclass Correlation Coefficients (ICC) have consistently ranged from .80 to .89 across the subscales, indicating high baseline measurement stability in the absence of active cognitive or behavioral interventions.

Factor Analysis

The latent structure of the Smoking Self-Efficacy Scales has undergone extensive psychometric modeling, utilizing both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA).

Exploratory Factor Analyses (EFA)

In initial scale development investigations (DiClemente, 1981, 1986; DiClemente et al., 1985), principal component analyses with varimax and oblique rotations consistently yielded a clean, three-factor orthogonal and oblique solution that accounted for over 60% of the total variance across candidate items. Items clustered unambiguously around:

1. High-arousal dysphoric states (frustration, anger, stress, depression);
2. Positive-affect social celebrations and interpersonal relaxation (parties, bars, coffee, relaxing with friends); and
3. Conditioned physiological or habitual triggers (morning awakening, acute cravings, needing a lift).

Confirmatory Factor Analyses (CFA) and Structural Equation Modeling

Velicer, DiClemente, Rossi, and Prochaska (1990) conducted definitive confirmatory factor analytic evaluations on large independent split-half samples (N = 1,000+). Multiple alternative models were tested, including a unidimensional (single-factor) model, an orthogonal three-factor model, a correlated three-factor model, and a hierarchical second-order model (where a general higher-order Self-Efficacy factor accounts for the shared variance among the three primary situational factors).

The correlated three-factor model and the hierarchical second-order model demonstrated superior fit over the unidimensional model across classical goodness-of-fit benchmarks:

• Goodness-of-Fit Index (GFI): > .92
• Comparative Fit Index (CFI): > .94
• Root Mean Square Error of Approximation (RMSEA): < .055 (indicating close structural fit)

Standardized item factor loadings across the three subscales were uniformly substantial, with the vast majority of items loading between .70 and .88 on their designated target latent factors, with negligible cross-loadings (typically < .20). For example, Item 19 (“When I am extremely anxious and stressed”) loaded at .85 on Negative Affect, while Item 1 (“At a bar or cocktail lounge having a drink”) loaded at .82 on Social/Positive.

Factorial Invariance Across Populations

Subsequent multigroup confirmatory factor analyses have confirmed measurement invariance (configural, metric, and scalar invariance) across diverse demographic categories:

• Gender Invariance: The three-factor latent structure operates equivalently for men and women without differential item functioning (DIF).
• Stage Invariance: The fundamental measurement structure remains invariant across smokers in Precontemplation, Contemplation, Preparation, Action, and Maintenance, confirming that changes in scale scores reflect true shifts in latent self-efficacy rather than alterations in how respondents conceptualize the items.

Instrument / Measurement Tool

The Smoking Self-Efficacy Scales can be implemented as either a comprehensive 20-item clinical inventory or a streamlined 9-item short form designed for rapid intake or digital monitoring.

• Test Type: Self-report psychological assessment / behavioral rating scale.
• Target Population: Current tobacco smokers, individuals preparing for smoking cessation, and former smokers maintaining abstinence across adult and adolescent populations.
• Administration Time: Approximately 4 to 6 minutes for the 20-item version; 1 to 2 minutes for the 9-item short form.
• Response Format: 5-point Likert-type scale fully anchored as follows:
  • 1 = Not at all confident
  • 2 = Not very confident
  • 3 = Moderately confident
  • 4 = Very confident
  • 5 = Extremely confident
• Subscale Structural Breakdown (20-Item Inventory):
  • Negative Affect Subscale (6 core items): Items 3, 5, 7, 8, 18, 19 (indices include frustration, family conflicts, anger, crisis, depression, extreme stress).
  • Social/Positive Subscale (6 core items): Items 1, 4, 6, 9, 10, 16 (indices include bars/lounges, spouse/friends smoking, celebrating, seeing others enjoy smoking, coffee, parties).
  • Habitual / Craving Subscale (5 to 8 items): Primary loading items 11, 13, 14, 15, 20 (with additional craving/conditioning indicators comprising items 2, 12, 17).
• Subscale Structural Breakdown (9-Item Short Form):
  • Negative Affect Subscale (3 items): Items 3, 6, 9 (Item 3: When I am very anxious and stressed; Item 6: When I am very angry about something or someone; Item 9: When things are not going my way and I am frustrated).
  • Social/Positive Subscale (3 items): Items 1, 4, 7 (Item 1: With friends at a party; Item 4: Over coffee while talking and relaxing; Item 7: With my spouse or close friend who is smoking).
  • Habitual / Craving Subscale (3 items): Items 2, 5, 8 (Item 2: When I first get up in the morning; Item 5: When I feel I need a lift; Item 8: When I realize I haven’t smoked for a while).
• Scoring and Computational Rules:
  • Subscale scores can be calculated either as raw summations or, more commonly, as mean item scores (sum of answered subscale items divided by the number of items in that subscale), producing an intuitive score range from 1.00 to 5.00.
  • A Total Self-Efficacy composite score can be derived by calculating the mean of all items.
  • Higher scores universally designate greater self-efficacy and superior perceived situational control to avoid smoking.
  • There are no reverse-coded items in the standard SSES instrument.
• Clinical Interpretation Framework:
  • Low Confidence (Mean 1.00 – 2.49): Represents extreme relapse vulnerability. Smoker lacks coping skills; high likelihood of immediate behavioral lapse upon encountering cues.
  • Moderate Confidence (Mean 2.50 – 3.74): Emerging self-regulatory control. Typical of smokers in Preparation or early Action. Cognitive reframing and situational behavioral rehearsals are warranted.
  • High Confidence (Mean 3.75 – 5.00): Robust resistance self-efficacy. Characteristic of established Action and Maintenance stages. Represents substantial resilience against cue-induced relapse.

Permissions & Fee and Test Year

The foundational Smoking Self-Efficacy Scale was initially introduced in the academic literature by Carlo C. DiClemente and colleagues in 1985, with the definitive psychometrically optimized 20-item and short-form inventories published by Wayne F. Velicer and colleagues in 1990.

Licensing and Intellectual Property: The instrument was developed with support from public research grants (primarily through the National Cancer Institute and the National Institutes of Health). In keeping with academic dissemination conventions for public health research instruments, the scale is placed in the public domain for research, academic, and clinical practice purposes.

Fees: There are no licensing fees or royalty payments required for non-commercial academic research, institutional education, or individual clinical use. Instruments, scoring rubrics, and related Transtheoretical Model measures are maintained and made accessible to the international research community through the Habits Lab at UMBC under the direction of Dr. Carlo C. DiClemente, and the Cancer Prevention Research Center (CPRC) at the University of Rhode Island. Users are expected to cite the primary source validation papers (DiClemente et al., 1985; Velicer et al., 1990) in all scientific publications and presentations.

References

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• Bandura, A. (1986). Social foundations of thought and action: A social cognitive theory. Prentice-Hall.
• Delahanty, J. C., DiClemente, C. C., Havas, S., & Langenberg, P. (2008). Smoking status and stages of change for dietary behaviors among WIC women. American Journal of Health Behavior, 32(6), 583–593. https://doi.org/10.5993/AJHB.32.6.3
• DiClemente, C. C. (1981). Self-efficacy and smoking cessation maintenance: A preliminary report. Cognitive Therapy and Research, 5(2), 175–187. https://doi.org/10.1007/BF01172525
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• DiClemente, C. C., Fairhurst, S. K., & Piotrowski, N. A. (1995). Self-efficacy and addictive behaviors. In J. E. Maddux (Ed.), Self-Efficacy, adaptation, and adjustment: Theory, research, and application (pp. 109–141). Plenum Press. https://doi.org/10.1007/978-1-4419-6868-5_4
• DiClemente, C. C., & Haug, N. (2001). Smoking cessation: Helping patients through the process. Journal of COPD Management, 2(4), 4–9.
• DiClemente, C. C., Prochaska, J. O., & Gibertini, M. (1985). Self-efficacy and the stages of self-change of smoking. Cognitive Therapy and Research, 9(2), 181–200. https://doi.org/10.1007/BF01204849
• Marlatt, G. A., & Gordon, J. R. (Eds.). (1985). Relapse prevention: Maintenance strategies in the treatment of addictive behaviors. Guilford Press.
• Perz, C. A., DiClemente, C. C., & Carbonari, J. P. (1996). Doing the right thing at the right time? The interaction of stages and processes of change in successful smoking cessation. Health Psychology, 15(6), 462–468. https://doi.org/10.1037/0278-6133.15.6.462
• Prochaska, J. O., & DiClemente, C. C. (1983). Stages and processes of self-change of smoking: Toward an integrative model of change. Journal of Consulting and Clinical Psychology, 51(3), 390–395. https://doi.org/10.1037/0022-006X.51.3.390
• Prochaska, J. O., DiClemente, C. C., & Norcross, J. C. (1992). In search of how people change: Applications to addictive behaviors. American Psychologist, 47(9), 1102–1114. https://doi.org/10.1037/0003-066X.47.9.1102
• Prochaska, J. O., Velicer, W. F., DiClemente, C. C., & Fava, J. (1988). Measuring processes of change: Applications to the cessation of smoking. Journal of Consulting and Clinical Psychology, 56(4), 520–528. https://doi.org/10.1037/0022-006X.56.4.520
• Velicer, W. F., DiClemente, C. C., Rossi, J. S., & Prochaska, J. O. (1990). Relapse situations and self-efficacy: An integrative model. Addictive Behaviors, 15(3), 271–283. https://doi.org/10.1016/0306-4603(90)90070-E

13. Items of the Scale (Questionnaire)