Explaining the effects of an intervention designed to promote evidence-based diabetes care: a theory-based process evaluation of a pragmatic cluster randomised controlled trial.
ABSTRACT: BACKGROUND: The results of randomised controlled trials can be usefully illuminated by studies of the processes by which they achieve their effects. The Theory of Planned Behaviour (TPB) offers a framework for conducting such studies. This study used TPB to explore the observed effects in a pragmatic cluster randomised controlled trial of a structured recall and prompting intervention to increase evidence-based diabetes care that was conducted in three Primary Care Trusts in England. METHODS: All general practitioners and nurses in practices involved in the trial were sent a postal questionnaire at the end of the intervention period, based on the TPB (predictor variables: attitude; subjective norm; perceived behavioural control, or PBC). It focussed on three clinical behaviours recommended in diabetes care: measuring blood pressure; inspecting feet; and prescribing statins. Multivariate analyses of variance and multiple regression analyses were used to explore changes in cognitions and thereby better understand trial effects. RESULTS: Fifty-nine general medical practitioners and 53 practice nurses (intervention: n = 55, 41.98% of trial participants; control: n = 57, 38.26% of trial participants) completed the questionnaire. There were no differences between groups in mean scores for attitudes, subjective norms, PBC or intentions. Control group clinicians had 'normatively-driven' intentions (i.e., related to subjective norm scores), whereas intervention group clinicians had 'attitudinally-driven' intentions (i.e., related to attitude scores) for foot inspection and statin prescription. After controlling for effects of the three predictor variables, this group difference was significant for foot inspection behaviour (trial group x attitude interaction, beta = 0.72, p < 0.05; trial group x subjective norm interaction, beta = -0.65, p < 0.05). CONCLUSION: Attitudinally-driven intentions are proposed to be more consistently translated into action than normatively-driven intentions. This proposition was supported by the findings, thus offering an interpretation of the trial effects. This analytic approach demonstrates the potential of the TPB to explain trial effects in terms of different relationships between variables rather than differences in mean scores. This study illustrates the use of theory-based process evaluation to uncover processes underlying change in implementation trials.
Project description:Understanding the intentions of dairy farmers towards mastitis control is important to design effective udder health control programs. We used the Theory of Planned Behavior (TPB) to explore the intentions of North-Western Ethiopian dairy farmers towards implementing non-specified mastitis control measures (nsMCMs) and towards implementing 4 specific MCMs. Face to face interviews were held with 134 dairy farmers to study associations between their intentions and any of three factors (attitude, subjective norm and perceived behavioral control) that, according to the TPB, determine intentions. The majority of the farmers (93%) had a positive intention to implement nsMCMs, whereas a smaller majority of farmers had the intention to implement the specific MCMs to improve udder cleaning (87%), to improve stall hygiene (78%), to improve feeding of cows (76%), and to perform foremilk stripping (74%). Farmers had a more positive attitude, but lower subjective norm and lower perceived behavioural control towards implementing nsMCMs compared with implementing most specific MCMs, although the subjective norms for stall hygiene and perceived behavioural control for improving feeding of cows were also low. Attitude was positively associated with intentions to implement nsMCMs, to improve cleaning of the udders, to improve stall hygiene and to implement foremilk stripping. Both the intention to improve udder cleaning and to implement foremilk stripping, were positively associated to subjective norms towards these MCMs. Our data can help tailor intervention programs aiming to increase the intention of Ethiopian dairy farmers to implement MCMs and thus to improve udder health in this country. We show that such programs should primarily focus on changing attitude and secondarily on improving the farmers' subjective norms.
Project description:Understanding broiler farmers' intention toward highly pathogenic avian influenza (HPAI) control is important to design successful HPAI control programs. We used Theory of Planned Behavior (TPB) to identify factors (i.e., attitude, subjective norm, and perceived behavioral control) associated with the intentions of Western-Java small-scale broiler farmers toward implementing cleaning and disinfection (C&D), vaccination, reporting, and stamping-out without or with 50% compensation. For this, 203 Western-Java farmers were interviewed. The majority of the farmers had a positive intention to implement C&D (89%), reporting (88%), and vaccination (80%). A lower number had a positive intention to join stamping-out both with 50% compensation (67%) and without any compensation (53%). Farmers had a more positive attitude and subjective norm, but lower perceived behavioral control toward one or more of the intentions to implement measures. Attitude was positively associated with intentions to implement C&D and vaccination. Subjective norm of veterinarians of integrated companies was positively associated with intentions to implement vaccination. Perceived behavioral control (i.e., money and time) was positively associated with intentions to implement C&D, vaccination, and stamping-out without any compensation. Results suggest that farmers are in favor of implementing preventive measures (i.e., C&D and vaccination) on HPAI control over facing the consequences of control measures (i.e., stamping-out), and HPAI control programs should primarily focus on incentivizing farmers complemented by programs aiming to improve farmers' attitude. Thus, policy should be emphasized to preventive measures rather than control measures. Financial incentive-based instruments (e.g., price and performance bonus) can be used to increase the intention of farmers to implement C&D and vaccination. Trained vaccinators might help to save the time needed to vaccinate the entire flock can increase the intention of farmers to vaccinate their chickens. Also, informational instruments (e.g., education and communication) can be used to change and to improve the attitude of farmers to implement both measures.
Project description:Individual energy-saving behaviours are crucial for reducing energy consumption, and research on the determinants of these behaviours has been increasing over the last decade. The aim of this study is to explore the determinants of two specific behaviours: 'switching off non-essential lights' and 'completely switching off electronic devices'. An extended model of the theory of planned behaviour (TPB) has been used as the theoretical research framework. The extension was implemented by considering two components (affective and cognitive) of the attitude towards these behaviours and then adding habit as a new variable. A two-waves study was conducted in which a convenience sample of Italian workers completed a questionnaire measuring the TPB constructs in relation to the two energy-saving behaviours (Time 1). The participants then completed another questionnaire a month later to assess self-reports of these behaviours (Time 2). The inclusion of habit improved the predictive power of the TPB, and the extended model was found to explain 65.5% and 76.1% of the variance in intentions and 16.2% and 22.9% of the variance in behaviours. Cognitive attitude, subjective norm, perceived behavioural control, and habit were significantly related to intentions, and perceived behavioural control was the strongest predictor. Habit moderated some relationships between the TPB constructs and intentions. Behaviours were associated directly only with intentions. The results of this study support the efficacy of the TPB model in predicting target behaviours; they also suggest some strategies that can be followed to promote these energy-saving behaviours.
Project description:INTRODUCTION: The implementation of complex medical interventions in daily practice is often fraught with difficulties. According to the iterative phase model proposed by the British Medical Research Council (MRC), the development, implementation and evaluation of complex interventions should be theory-driven. A conceptual model that seems to be a promising framework is the Theory of planned behaviour (TPB). In our study we aimed to develop and validate a generic and multifaceted questionnaire based on the TPB to detect physicians' willingness to implement complex medical interventions and the factors influencing this willingness. METHODS: The questionnaire was developed according to the literature and was informed by previous qualitative research of our department. It was validated on the example of an electronic library of decision aids, arriba-lib. The sample consisted of 181 General Practitioners (GPs) who received a training regarding arriba-lib and subsequently filled in the questionnaire, assessing the TPB variables attitude, subjective norm, perceived behaviour control and intention. Follow-up assessments were conducted after two (assessing retest reliability) and eight weeks (assessing target behaviour). We performed a confirmatory factor analysis investigating the factorial structure of our questionnaire according to the TPB. Beside the calculation of the questionnaire's psychometric properties we conducted a structural equation model and an ordinal regression to predict actual behaviour regarding the installation and application of arriba-lib. RESULTS: The postulated three factorial model (attitude, subjective norm, perceived behaviour control) of our questionnaire based on the TPB was rejected. A two factorial model with a combined factor subjective norm/perceived behaviour control was accepted. The explained variance in the ordinal regression was low (Nagelkerke's R(2)=.12). Neither attitude nor intention were able to predict the use or non-use of arriba-lib (attitude: p=.68, intention: p=.44). For the combined factor subjective norm/perceived behaviour control a significant, but small effect (p=.03) was shown. CONCLUSIONS: The TPB is not an adequate theoretical framework to guide the development of a generic questionnaire in the context of the implementation of complex interventions. To enable the successful implementation of complex medical interventions evaluators have to go through the whole development and evaluation process according to the MRC-model, without short cuts. Further, it has to be discussed if a generic instrument can be valid and useful. Regarding the TPB a publication bias regarding the theory's applicability might have to be considered.
Project description:BACKGROUND: Long term management of patients with Type 2 diabetes is well established within Primary Care. However, despite extensive efforts to implement high quality care both service provision and patient health outcomes remain sub-optimal. Several recent studies suggest that psychological theories about individuals' behaviour can provide a valuable framework for understanding generalisable factors underlying health professionals' clinical behaviour. In the context of the team management of chronic disease such as diabetes, however, the application of such models is less well established. The aim of this study was to identify motivational factors underlying health professional teams' clinical management of diabetes using a psychological model of human behaviour. METHODS: A predictive questionnaire based on the Theory of Planned Behaviour (TPB) investigated health professionals' (HPs') cognitions (e.g., beliefs, attitudes and intentions) about the provision of two aspects of care for patients with diabetes: prescribing statins and inspecting feet.General practitioners and practice nurses in England and the Netherlands completed parallel questionnaires, cross-validated for equivalence in English and Dutch. Behavioural data were practice-level patient-reported rates of foot examination and use of statin medication. Relationships between the cognitive antecedents of behaviour proposed by the TPB and healthcare teams' clinical behaviour were explored using multiple regression. RESULTS: In both countries, attitude and subjective norm were important predictors of health professionals' intention to inspect feet (Attitude: beta = .40; Subjective Norm: beta = .28; Adjusted R2 = .34, p < 0.01), and their intention to prescribe statins (Attitude: beta = .44; Adjusted R2 = .40, p < 0.01). Individuals' self-reported intention did not predict practice-level performance of either clinical behaviour. CONCLUSION: Using the TPB, we identified modifiable factors underlying health professionals' intentions to perform two clinical behaviours, providing a rationale for the development of targeted interventions. However, we did not observe a relationship between health professionals' intentions and our proxy measure of team behaviour. Significant methodological issues were highlighted concerning the use of models of individual behaviour to explain behaviours performed by teams. In order to investigate clinical behaviours performed by teams it may be necessary to develop measures that reflect the collective cognitions of the members of the team to facilitate the application of these theoretical models to team behaviours.
Project description:OBJECTIVE: To determine the intention to use hearing aids (HAs) by applying the theory of planned behavior (TPB). DESIGN: The TPB is a widely used decision-making model based on three constructs hypothesized to influence the intention to perform a specific behavior; namely, "attitude toward the behavior", "subjective norm", and "behavioral control". The survey was based on a TPB-specific questionnaire addressing factors relevant to HA provision. STUDY SAMPLE: Data from 204 individuals reporting hearing problems were analyzed. Different subgroups were established according to the stage of their hearing help-seeking. RESULTS: The TPB models' outcome depended on the subgroup. The intention of those participants who had recognized their hearing problems but had not yet consulted an ear, nose, and throat specialist was largely dominated by the "subjective norm" construct, whereas those who had already consulted an ear, nose, and throat specialist or had already tried out HAs were significantly influenced by all constructs. The intention of participants who already owned HAs was clearly less affected by the "subjective norm" construct but was largely dominated by their "attitude toward HAs". CONCLUSION: The intention to use HAs can be modeled on the basis of the constructs "attitude toward the behavior", "subjective norm", and "behavioral control". Individual contribution of the constructs to the model depends on the patient's stage of hearing help-seeking. The results speak well for counseling strategies that explicitly consider the individual trajectory of hearing help-seeking.
Project description:Pragmatic trials of implementation interventions focus on evaluating whether an intervention changes professional behaviour under real-world conditions rather than investigating the mechanism through which change occurs. Theory-based process evaluations conducted alongside pragmatic randomised trials address this by assessing whether the intervention changes theoretical constructs proposed to mediate change. The Ontario Printed Educational Materials (PEM) cluster trial was designed to increase family physicians' guideline-recommended prescription of thiazide diuretics. The trial found no intervention effect. Using the theory of planned behaviour (TPB), we hypothesised that changes in thiazide prescribing would be reflected in changes in intention, consistent with changes in attitude and subjective norm, with no change to their perceived behavioural control (PBC), and tested this alongside the RCT.We developed and sent TPB postal questionnaires to a random sub-sample of family physicians in each trial arm 2 months before and 6 months after dissemination of the PEMs. We used analysis of covariance to test for group differences using a 2 × 3 factorial design. We content-analysed an open-ended question about perceived barriers to thiazide prescription. Using control group data, we tested whether baseline measures of TPB constructs predicted self-reported thiazide prescribing at follow-up.Four hundred twenty-six physicians completed pre- and post-intervention questionnaires. Baseline scores on measures of TPB constructs were high: intention mean = 5.9 out of 7 (SD = 1.4), attitude mean = 5.8 (SD = 1.1), subjective norm mean = 5.8 (SD = 1.1) and PBC mean = 6.2 (SD = 1.0). The arms did not significantly differ post-intervention on any of the theory-based constructs, suggesting a possible ceiling effect. Content analysis of perceived barriers suggested post-intentional barriers to prescribing thiazides most often focused on specific patient clinical characteristics and potential side effects. Baseline intention (β = 0.63, p < 0.01) but not PBC (β = 0.04, p = 0.78) predicted 42.6 % of the variance in self-reported behaviour at follow-up in the control group.Congruent with the Ontario Printed Educational Messages trial results and aligned with the TPB, we saw no impact of the intervention on any TPB constructs. The theoretical basis of this evaluation suggests possible explanations for the failure of the PEM intervention to change professional behaviour, which can directly inform the design and content of future theory-based PEM interventions to change professional behaviour.ISRCTN, Canada ISRCTN72772651.
Project description:<h4>Objective</h4>To identify factors associated with intention to attend a hypothetical eye health test and provide an evidence base for developing an intervention to maximise attendance, for use in studies evaluating glaucoma screening programmes.<h4>Design</h4>Theory-based cross-sectional survey, based on an extended Theory of Planned Behaviour (TPB) and the Common Sense Self-Regulation Model, conducted in June 2010.<h4>Participants</h4>General population including oversampling from low socioeconomic areas.<h4>Setting</h4>Aberdeenshire and the London Boroughs of Lewisham and Southwark, UK.<h4>Results</h4>From 867 questionnaires posted, 327 completed questionnaires were returned (38%). In hierarchical regression analysis, the three theoretical predictors in the TPB (Attitude, Subjective norm and Perceived Behavioural Control) accounted for two-thirds of the variance in intention scores (adjusted R(2)=0.65). All three predictors contributed significantly to prediction. Adding 'Anticipated regret' as a factor in the TPB model resulted in a significant increase in prediction (adjusted R(2)=0.74). In the Common Sense Self-Regulation Model, only illness representations about the personal consequences of glaucoma (How much do you think glaucoma would affect your life?) and illness concern (How concerned are you about getting glaucoma?) significantly predicted. The final model explained 75% of the variance in intention scores, with ethnicity significantly contributing to prediction.<h4>Conclusions</h4>In this population-based sample (including over-representation of lower socioeconomic groupings), the main predictors of intention to attend a hypothetical eye health test were Attitude, Perceived control over attendance, Anticipated regret if did not attend and black ethnicity. This evidence informs the design of a behavioural intervention with intervention components targeting low intentions and predicted to influence health-related behaviours.
Project description:For people with dementia, patient-centred care should involve timely explanation of the diagnosis and its implications. However, this is not routine. Theoretical models of behaviour change offer a generalisable framework for understanding professional practice and identifying modifiable factors to target with an intervention. Theoretical models and empirical work indicate that behavioural intention represents a modifiable predictor of actual professional behaviour. We identified factors that predict the intentions of members of older people's mental health teams (MHTs) to perform key behaviours involved in the disclosure of dementia.Postal questionnaire survey.Professionals from MHTs in the English National Health Service.We selected three behaviours: Determining what patients already know or suspect about their diagnosis; using explicit terminology when talking to patients; and exploring what the diagnosis means to patients. The questionnaire was based upon the Theory of Planned Behaviour (TPB), Social Cognitive Theory (SCT), and exploratory team variables.Behavioural intentions.Out of 1,269 professionals working in 85 MHTs, 399 (31.4%) returned completed questionnaires. Overall, the TPB best explained behavioural intention. For determining what patients already know, the TPB variables of subjective norm, perceived behavioural control and attitude explained 29.4% of the variance in intention. For the use of explicit terminology, the same variables explained 53.7% of intention. For exploring what the diagnosis means to patients, subjective norm and perceived behavioural control explained 48.6% of intention.These psychological models can explain up to half of the variation in intention to perform key disclosure behaviours. This provides an empirically-supported, theoretical basis for the design of interventions to improve disclosure practice by targeting relevant predictive factors.
Project description:This study aimed to quantify correlations between theory of planned behaviour (TPB) variables and (i) intentions to consume alcohol and (ii) alcohol consumption. Systematic literature searches identified 40 eligible studies that were meta-analysed. Three moderator analyses were conducted: pattern of consumption, gender of participants and age of participants. Across studies, intentions had the strongest relationship with attitudes (r+ = .62), followed by subjective norms (r+ = .47) and perceived behavioural control (PBC; r+ = .31). Self-efficacy (SE) had a stronger relationship with intentions (r+ = .48) compared with perceived control (PC; r+ = -.10). Intention had the strongest relationship with alcohol consumption (r+ = .54), followed by SE (r+ = .41). In contrast, PBC and PC had negative relationships with alcohol consumption (r+ = -.05 and -.13, respectively). All moderators affected TPB relationships. Patterns of consumption with clear definitions had stronger TPB relations, females reported stronger attitude-intention relations than males, and adults reported stronger attitude-intention and SE-intention relations than adolescents. Recommendations for future research include targeting attitudes and intentions in interventions to reduce alcohol consumption, using clear definitions of alcohol consumption in TPB items to improve prediction and assessing SE when investigating risk behaviours.