Effectiveness of a theory-based sun-safe randomised behavioural change trial among Australian adolescents.

OBJECTIVE: Sun safety is crucial for preventing skin cancer. This study evaluated a school-based intervention based on the theory of planned behaviour (TPB), which aimed to encourage sun-protective behaviour among adolescents. METHODS: Secondary school students (N = 382; 61.1% female; Mage  = 13.73 y) in Queensland, Australia, participated in the study. Schools were randomly allocated to an intervention or control group. The intervention focussed on fostering positive attitudes, increasing perceptions of normative support, and strengthening control perceptions. Participants completed questionnaires assessing the TPB variables and sun-protective behaviour (weekday and weekend) 1 week before intervention (time 1), 1 week after intervention (time 2), and 4 weeks after intervention (time 3). RESULTS: With baseline between-group differences in TPB variables matched, repeated-measures multivariate analysis of variance was used to evaluate the Time × Condition effects across time. Multigroup comparisons using path models traced the intervariable changes. From times 1 to 3, a significant improvement in weekend sun-protective behaviour was identified in the intervention group (but not the control group), whereas cognitions showed no significant changes across time for either conditions. Multigroup comparisons on path coefficients between the intervention and control group participants indicated that the intervention group members formed stronger positive associations between perceived behavioural control and intention at time 2 and between perceived control and behaviour at time 3. CONCLUSION: The significant behavioural change on weekends highlights the value of targeting control perceptions, which may encourage adolescents' sun-protective behaviour. Further studies are needed to understand the absence of significant changes in weekday sun-safe behaviour among this at-risk cohort.

Charitable donations and the theory of planned behaviour: A systematic review and meta-analysis.

Given the predominance of the theory of planned behaviour (TPB) to represent the psychological determinants underlying people's charitable decisions, the present study synthesised the model's key relationships, using meta-analysis, and tested the predictive utility of the model for charitable giving encompassing donations of blood, organs, time, and money. Given its relevance to altruistic decisions, the impact of moral norm was assessed also. A systematic literature review identified 117 samples (from 104 studies) examining donation intentions and/or prospective behaviour using TPB measures. The sample-weighted average effects for all associations were moderate-to-strong with perceived behavioural control (PBC) most strongly associated with intention (r+ = 0.562), followed by moral norm (r+ = 0.537), attitude (r+ = 0.507), and subjective norm (r+ = 0.472). Intention (r+ = 0.424) showed stronger associations with prospective behaviour than PBC (r+ = 0.301). The standard TPB predictors explained 44% of variance in intention (52% including moral norm). Intention and PBC explained 19% of variance in behaviour. A number of TPB associations showed differences when analysed for moderator variables such as length of follow-up for prospective behaviour and type of target behaviour. Stronger associations were found for the (subjective and moral) norm-intention associations among some of the different types of giving behaviours, especially for donating organs and time. Overall, the large proportion of variance explained by the TPB predictors especially for intention highlights those cognitions associated with people's plans to give, informative for charities reliant on people's propensity to give.

Predicting sun-protective intentions and behaviours using the theory of planned behaviour: a systematic review and meta-analysis.

OBJECTIVE: To synthesise theory of planned behaviour (TPB) relationships, using meta-analysis, and test the predictive utility of the model for sun protection behaviour. DESIGN: Thirty-eight samples were identified via database/manual searches and academic society posts based on the criteria: measuring sun-protective intentions and/or prospective behaviour; using the TPB/theory of reasoned action as a basis of measurement; and providing bivariate correlations for at least one relevant TPB association. MAIN OUTCOME MEASURES: Sun-protective intentions and behaviours. RESULTS: The sample-weighted average effects were moderate-to-strong with attitudes showing the strongest association with intention (r+ = 0.494), followed by perceived behavioural control (PBC; r+ = 0.451), and subjective norm (r+ = 0.419). Intentions showed a stronger association with prospective behaviour (r+ = 0.486) compared to PBC (r+ = 0.314). A total of 39% of variance in intentions and 25% of variance in behaviour were explained. Publication bias was not evident. Moderator analyses showed that TPB associations were stronger when measures specified the Target, Action, Context and Time; in non-student samples; and when follow-up exceeded two weeks. CONCLUSION: Despite recent criticism, this review shows that the TPB explains a large amount of variance in sun protection and that TPB associations are robust across different populations.