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Following on from the investigation of individual variables and their effect on behaviour, their joint effect in the process described by the HAPA was examined. Of the three variables hypothesised to predict intention, outcome expectancies

and self-efficacy were successful in multiple regression analyses. Threat,

however, was not found to be a predictor of intention. This particular finding is not in conflict with the HAPA. Although there is a link between threat and

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intentionin the HAPA, Schwarzer (1992) hypothesised that self-efficacy and

outcome expectancies are the major predictors of an intention, with threat acting

as a ‘distal antecedent’ which helps to activate outcome expectancies. He suggested that the link between threat and intention may, in fact, be insubstantial

if outcome expectancies are already well established. This suggestion is echoed in

the PAP which stresses that a minimum level of threat is necessary^^ before people can start contemplating what possible actions they could take. If they are already at the stage of thinking about acting and weighing up the pros and cons (cf. having outcome expectancies), then perceived threat becomes less important (Weinstein, 1988). Results from the analyses of the PAP data in this study suggest that a large percentage of the sample were at the maintenance stage where threat would not be expected to be a predictor of intention. However, Schwarzer (1992) also hypothesised that self-efficacy would dominate in the explanation of intention, followed by outcome expectancies. The results of this study did not support this hypothesis, certainly for the two concurrent analyses where outcome expectancies explained the majority of the variance with self-

efficacy only adding a small percentage. The beta values were also much lower

for self-efficacy, indicating that it was a less significant predictor. However, the

analyses over time, measuring health beliefs before screening and intention

following screening indicated a stronger effect of self-efficacy than in the concurrent analyses. Overall, though, the amount of variance in intention

explained by these variables was less when measured over time. Over time, prior

intention was the strongest predictor. This suggests that overall, health beliefs

were less stable predictors of intention over time.

3.5.4.2 Predictive power of motivation phase Predicting the number o f behaviour changes

In terms of the prediction of behaviour by the motivation phase, it was expected, according to the model, that intention and self-efficacy would be the best

For details of these studies, see chapter 1: hitroduction, pages 25-26.

Stage 2 of the PAP is ‘aware of tlie issue but not personally engaged’ whereas stage 3 is ‘engaged and deciding what to do’. Weinstein (1988) suggests that perceived susceptibility is a predictor of becoming engaged, i.e. only once a person perceives a personal threat to their healtli will they start thinking about what tliey can do to reduce Üieir risk.

predictors of behaviour. This was not found to be the case. Only threat was found to be a predictor of the number of behaviour changes made and explained only a small amount of variance. This small amount of explanation of variance in behaviour by health beliefs is greater than some studies using the earlier social cognition models (e.g. Conner & Norman (date)^^), but less than others (e.g. Champion, 1985^^). However, the HAPA acknowledges that the motivation phase is only the first step towards behaviour change, so it may not be expected to explain much of the variance in behaviour anyway.

Predicting specific behaviour changes

In terms of the results of the prediction of the specific behaviour changes by the motivation phase, again intention was not found to be the best predictor of exercise behaviour change. (Exercise was the only specific behaviour change where the motivation phase was able to discriminate between changers and non­ changers). However, intention was found to be an important discriminator in the multivariate analyses, just less important than threat and outcome expectancies.

The significant discriminant fianction formed by the four variables of the motivation phase was able to classify a reasonably large percentage of exercise changers and non-changers overall (78.6% before screening and 70.4% after screening). A previous study using discriminant function analyses to investigate an extension of the HBM in the prediction of attendance at screening (King,

1982) found that 82.3% of the subjects could be correctly classified by including all the variables in the fimction. Although many of the variables in that study were similar to those in the motivation phase of the present study, the former also included extra causal attribution variables which correlated highly with the discriminant function. However, although the overall classification rate was high in King’s study, the attenders were more easily classified (87.7%) than the non- attenders (69.0%). A similar result was found in the study of worksite screening reported in Chapter two of this thesis which showed that the TRA was able to

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classify 72.4% of the subjects overall, but 84.4% of the attenders compared to only 53% of the non-attenders. Therefore, although the HAPA motivation phase, an extended version of the TRA, used in the present study was no more successful than the TRA in the overall classification of subjects, it provided a more even classification of the two groups. Nevertheless, the outcome behaviours, the sample sizes and types of population were different between the present study and the previous two studies which questions the meaningftilness of such a direct comparison.

The HAPA’s motivation phase was not found to be useful in predicting dietary or smoking behaviour change. Perhaps certain behaviours depend more heavily on the action phase of the model.

Again, differences before and after screening support the prediction that health beliefs would be less important following screening.

3.5.4.3 The link between the motivation and action phases

To test the HAPA further, the link between the motivation and action phases was investigated. The results of the correlations suggested that there were links between intention and action plans. Although there was less evidence of relationships between self-efficacy and the action phase, there were strong links with evaluation o f decision. Evaluation o f decision consists of questions relating to the amount of effort a subject is prepared to putting into carrying out the decision, etc. Thus this finding is in line with Schwarzer’s hypothesis (1992) that

self-efficacy has an influence on the amount of effort that will be invested and the

commitment to carrying out the behaviour.

3.5.4.4 Overall summary regarding the HAPA

The research question was whether the HAPA was a useful predictive and explanatory model for behaviour change in the context of CHD screening. The study tested (1) the internal structure of the motivation phase, (2) the prediction of behaviour by the motivation phase (3) the link between the motivation and action phases and (4) the individual effect of variables suggested by the action phase on behaviour. The prediction of behaviour by the action phase was not

tested as such due to its lack of theoretical coherence (although the HAPA was used as a framework, the operationalisations of the variables were derived from the theories of Bagozzi (1992) and Gollwitzer (1993)). Furthermore there was some missing data.

First, the study found that threat was not a predictor of intention. Only outcome

expectancies and self-efficacy were found to be so. This internal structure of the

motivation phase was as the HAPA predicts if outcome expectancies are well established which is likely to be the case in this sample. However, self-efficacy

was not as dominant as expected.

Second, the overall predictive power of the motivation phase was not much better than the TRA when compared to previous studies using the latter model. The important predictors were not as the HAPA predicts. Intention and self-efficacy

were less important and threat most important. The effect of the variable threat

was where there was most disagreement with the HAPA. Threat did not predict

intention, but did predict behaviour and was a more important predictor of

behaviour than intention. This seems to indicate a direct link from threat to the action phase, not via intention. Perhaps high threat predicts behaviour change because it means there is more to change. This hypothesis was tested by

correlating the variable threat with initial health behaviour levels, i.e. behavioural ladder scores before screening. The correlations between threat and initial exercise score (r=-.36, p=.001) and initial dietary score (r=-.23, p-.04) were negative and significant. These results imply that, for these behaviours, high threat is related to low initial behaviour levels, thus supporting the hypothesis. Third, there were links between intention and self-efficacy and the action phase as the HAPA predicts.

Fourth, although the action phase was not tested as a whole, the results suggest that these variables could be useful in predicting behaviour and should be further developed and tested with different populations.

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however, to question the structure of the model in terms of the importance of

threat, a question requiring further study, particularly in this context of behaviour

change following screening.