The Stages of Change construct is one of the pillars of TTM theory. It reflects the individual’s motivational readiness to make a specific behaviour change. Accurate staging is perhaps the most crucial aspect of using TTM for developing health-related interventions 29. To date, two major methods have been used for assigning stage classifications: staging algorithm and multidimensional questionnaire 30. The staging algorithm approach uses a small number of questionnaire items to determine the participant’s stage. In the second approach, each Stage of Change is measured through a set of questionnaire items. With few exceptions (e.g. 19), a number of applications of TTM to various health behaviours employed staging algorithms 21,25,31. The staging algorithm used in this study to classify participants into one of the five stages of change depends on the assessment of recent past behaviour and the willingness to change behaviour. In fact, in order to be allocated to one of the earlier stages (Pre-contemplation, Contemplation, Preparation), participants are required to state their intent to donate blood in the near future. Nevertheless, Action and Maintenance stages require the demonstration of both intention and regular past experience of blood donation. Research suggests that past behaviour is a significant predictor of future behaviour for regular and experienced donors (5 or more previous donations), and intentions were predictive of occasional donors (4 or fewer previous donations) 32,33. For this reason, intentions outweigh past behaviour in the earlier stages of TTM. Consistent with previous research (e.g. 21,25), participants in this study were predominantly categorized into the pre-preparation stages accounting for 78.6% which mirrors the deterrence of participants in donating blood and the need to trigger a range of motives to induce progression across stages of change. This shall therefore contribute in the development and promotion of stage-matched interventions that harness the relevant and modifiable stage transitions determinants.
With regards to domination of the processes of change across the five stages of change, previous studies based on TTM demonstrated that experiential processes benefit progression through the earlier stages of behaviour change while behavioural processes have greater importance during later stages. In the current study, both sets of Processes of Change were significantly lower for individuals in Pre-contemplation than those in further stages. This result supports the hypothesis of the TTM, which is that the more advanced an individual is in Stage of Change, the more frequently they will use the Processes of Change. Indeed, pre-contemplators are unmotivated and unaware of the need to change, thus harnessing fewer strategies towards behaviour change 26,34. Moreover, individuals in Preparation stage were active on almost every process of change owing to the fact that prepared individuals are acutely motivated to experiment with changing behaviour employing therefore various methods that combine intention and behaviour criteria to improve their determination in favour of change. Aside from Consciousness raising and Self-liberation, all the processes of change peaked in the Maintenance stage. It is presumed that people in Maintenance stage do not apply Processes of Change as frequently as do people in earlier stages, yet, they need to stabilize their behaviour and work to avoid temptation and prevent relapses. In fact, most of the Processes of Change (e.g. counter conditioning, stimulus control) play a crucial role in helping individuals cope with high-risk situations that are associated to relapse. Based on ANOVA’s findings, Dramatic relief has no effect on the staging progress. Excepting Reinforcement Management, all the behavioural processes obtained very large effect sizes. Additionally, individuals in Action stage reported using Self-liberation strategy more often than those in other stages. This is not surprising, as people in Action stage need to learn how to consolidate their commitments, hence seeking interventions that strengthen their belief and increase their autonomy to change 35. In accordance with previous studies, results demonstrated that people in Action and Maintenance stages emphasize the usage of both counter-conditioning and stimulus control for coping with temptations 30,31. Processes of Change offer theoretical valid strategies to help individuals progressively acquire new healthy behaviours. Given that specific Processes of Change are optimally effective at each stage of change, delivering tailored interventions that integrate the appropriate processes with the stages will promote behavioural change. However, failing to match Processes of Change to an individual’s Stage of Change can hamper the expected usefulness of interventions 36.
Alike processes of change, decisional balance also varies significantly across stages of change. The construct of Decisional Balance refers to the individual’s weighing the potential benefits and costs involved with changing behaviour. While most TTM studies put emphasis on two-dimensional scale to measure decisional balance 23, some TTM applications yielded a different scale of more than two factors 37,38. In the current study, the patterns of change in the pros and cons across the stages of change were found to be revealing. It was speculated that pros increase, and cons decrease from earlier to later Stages of Change defining a crossover pattern between Contemplation and Action stages. This result was achieved in Physical Cons and Pros and the crossover pattern occurs in the Preparation stage. However, the magnitude of change was not as large as expected. Physical cons of blood donation behaviour change significantly outweighed the pros in the Precontemplation stage and were lower than pros in the advanced stages. Indeed, individuals in earlier stages recall physical cons more often than those in further stages. In contrast, eligibility cons and pros did not yield a significant statistical difference across stages. Nonetheless, the pros increase slightly as individuals move toward the later stages with a small decrease in the Preparation stage. This result confirms that the progression across stages requires additional motivation by outbalancing the advantages of blood donation behaviour change over possible barriers. Moreover, eligibility cons did not decrease significantly across stages as did physical cons. This finding may have resulted from the possibility that regardless of their Stages of Change, blood donors may face rejection and deferral due to low haemoglobin level, high blood pressure and medication intake, to cite but a few 39. Overall, Decisional Balance has demonstrated to be a good predictor through the stages of change.
Another major construct of TTM is Self-efficacy which refers to the perception and situational confidence that individuals have in their abilities to adopt and maintain the desired behaviour change even in difficult circumstances that often trigger relapse 14. Research on TTM suggests that Self-efficacy increases in an almost linear fashion as the Stages of Change advances. Consistent with this, the Self-efficacy scores in the present study varied and rose significantly across stages. Contemplators had higher baseline of Self-efficacy scores than pre-contemplators and lower level than participants in advanced Stages of Change. In addition, participants in Preparation stage reported similar level of confidence to those in Contemplation stage. Perhaps individuals in preparation stage demonstrate ambivalence about their readiness to engage in the behavioural change. Moreover, participants identified in action and maintenance stages expressed the highest levels of self-efficacy with regard to blood donation in high-risk situations. This indicates that Self-efficacy is strongly influenced by performing the behaviour and that individuals in later stages are, by default, acting towards the behaviour change. The results obtained in this study provide evidence supportive of the applicability of the self-efficacy construct to actively change blood donation behaviour. This construct is genuinely considered a crucial resource to maintaining behaviour changes and preventing stage regression.
With respect to the associations among the TTM constructs, significant positive correlations were observed between the two dimensions of Processes of Change and Pros and Self-efficacy. Hence, TTM-based interventions that promote the usage of behavioural and cognitive Processes of Change should increase Pros and Self-efficacy accordingly. Eligibility cons were positively related to all TTM constructs and particularly to the pros of donating. A possible explanation is that even though individuals have eligibility concerns to donate blood, they outbalance their perception of the benefits of donating over these concerns. Moreover, scores on both cognitive and behavioural processes were not correlated with physical cons of blood donation. Consistent with this outcome, many studies have reported that physical concerns are less prominent in behaviour change 23,40. Additionally, a significant negative correlation was found between self-efficacy and physical cons. Therefore, it may be the case that as individuals gain confidence in their ability to donate blood, they start to attach little importance to the associated physical barriers. The highest correlation was found between the two dimensions of Processes of Change further supporting prior studies in which a tight association was perceived among processes 41.
Threats to validity
Despite the interest of this research, a number of threats to validity of reported conclusions are worth highlighting.
Construct validity refers to the extent to which a test measures the construct it claims to be measuring 42. In this regard, due to the lack of a standardized measurement instrument for stage classification, the validity and reliability of staging algorithms have not yet been established 43. To mitigate this threat, the staging algorithm used in this study was elaborated on the basis of validated measures 21,28. Moreover, the items developed to measure Processes of Change, Decisional Balance and Self-efficacy were derived from a selection of validated TTM measures in various health behaviours including blood donation. Despite the attempt to refine and adapt these measures to our study population, they may not have appropriately captured TTM constructs from the participants’ perception.
Internal validity refers to the degree to which conclusion about causal relationships can be made 42. The internal validity of the present study could be threatened by a bias towards the instrumentation adopted. In fact, the questionnaire used in this study to gather data relied on a self-report format, leading to possible response bias due to a lack of validity and reliability 44. Nevertheless, self-report measures are largely considered as a pertinent tool in health behavioural research 45,46.
External validity refers to the extent to which findings can be validly generalized across various settings 42. In this study, the size of the final sample was convenient, however, it comprises somewhat a restricted range of donors in advanced stages which was not representative of the rest of the blood donors’ population. This may jeopardize the generalizability of the findings of this study. It is, therefore, necessary to conduct further assessment that includes greater percentages of regular donors to benefit the yielded measures.