SCALE STRUCTURE AND RELIABILITY

All the scales used in this study were assessed for internal consistency and for dimensionality. Accordingly, internal consistency among the items of each scale was tested using the Cronbach’s alpha procedure (Cronbach, 1951), and to analyse the underlying dimensionality, the Principle Component Analysis was used. The procedure also determined which items to integrate into the corresponding composite measures of the respective scales.

132 5.3.1 Scale Structures

Scales structures were determined by employing Principal Component Analysis with Varimax rotation. A minimum loading criterion of 1 was adopted to recognise a factor, while 0.5 was considered the minimum loading criterion of the items on a given factor.

Any item with a value greater than this load criterion for more than one factor in a scale was deemed to be cross-loaded. Furthermore, any communality value below 0.6 was considered inadequate. In order to confirm the adequacy of the sample size for factor analysis, Kaiser-Meyer-Olkin (KMO) Measure of Sampling Adequacy tests were also carried out. The KMO values with regards to each scale were well above the required threshold of 0.50 (Kaiser & Rice, 1974) indicating the adequacy of the sample size for the respective scale. A summary of the Principal Component Analysis after removing certain items from some scales is presented in Table 5-2 and each variable is described in the following sections.

Table 5-2 – Results of the Principal Component Analysis

Scale

Perceived Music Message Congruence 0.83 3.36 84.62

Perceived Message Complexity 0.79 2.26 75.36

Dependent Variables

Psychological Discomfort 0.75 2.54 84.59

Cognitive Load 0.79 2.27 75.53

Attitude towards Advertisement 0.85 3.42 85.46

Covariate

Need for Cognition 0.88 3.68 73.62

5.3.1.1 Independent Measures

The five items in Perceived Message Complexity were analysed, and as anticipated, the scale was unidimensional. However, two items (DF4 and DF5) were removed from the scale due to low communality scores. The total variance explained by this factor without the above two items was 75.4%. Similarly, four items used in the perceived Music Message Congruence scale were also unidimensional, explaining 84.6%

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variance. The results did not show any prominent issues with communality values.

Thus, all the items of this scale were retained for further analysis.

5.3.1.2 Process Variables

There were two variables considered under process variables -Psychological Discomfort and Cognitive Load. The Psychological Discomfort scale, consisting of three items, produced a single factor explaining a total variance of 84.6%. Similarly, Cognitive Load scale, consisting of five items, produced a single factor explaining 61.5% of total variance. However, two items (CL4 and CL5) were associated with low communality values and therefore deleted from the scale. The new three item scale explained 75.5% of the total variance.

5.3.1.3 Output Variables

Out of the five output variables mentioned in the conceptual model, only the Attitude towards Advertisement was measured through a semantic-differential scale. The other four memory-related variables were measured using special procedures explained in Section 4.3.3 of Chapter 4. Hence, only Attitude towards Advertisement was considered in this analysis and it produced a single factor explaining 85.5% of the total variance. There was no apparent issue associated with items in the scale and therefore all the items were retained.

5.3.1.4 Covariates

Out of the two covariates, only Need for Cognition was measured with a scale. A different method was employed to calculate the Working Memory Capacity, which is described in Section 4.3.4.2 of Chapter 4.

The modified scale used for measuring Need for Cognition consisted of five items. The initial analysis carried out on these items revealed that the scale was unidimensional with a factor explaining 73.6% of the total variance. As expected, no item appeared to be problematic and hence all items were retained in for further analysis.

134 5.3.2 Scale Reliability

Following the factor analysis, all the scales were analysed for their internal consistency with the use of Cronbach’s alpha procedure. The summary of final reliability scores are listed in Table 5-3.

Table 5-3 - Reliability Scores of the Scales Used

Scale Cronbach’s

Alpha Independent Variables

Perceived Music Congruence 0.96

Perceived Message Complexity 0.84

Dependent Variables

Psychological Discomfort 0.91

Cognitive Load 0.84

Attitude Towards Advertisement 0.97

Covariates

Need for Cognition 0.91

All the scales demonstrated an acceptable level of alpha values well above 0.70.

However, certain items in some scales were deleted in the previous analysis for further improvement, except for the Perceived Music Message Congruence and Attitude scales.

Despite the existing alpha values of these two scales being well within the acceptable range, the analysis indicated that the removal of FT4 from the Congruence scale and ATT2 from the Attitude scale would further increase reliability. Hence, the items were omitted from the respective scales for further analysis.

5.3.2.1 Inter-coding Reliability

Immediate and delayed recall measures were obtained through a set of open-ended questions. Since the responses were not listed for the participants to choose from, the score had to be obtained by marking the answers manually. Therefore, obtaining impartial as well as consistent results was important. In achieving this objective, the written answer-scripts were marked by two independent markers who were unaware of the actual research objectives, and the inter-coding consistency was checked with the correlation coefficients of marks in each category.

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Table 5-4 - Inter-Coding Consistency of Recall Tests

Category or Recall Correlation Coefficient

Sig

Immediate

Category Recall 0.95 .00

Brand Recall 0.97 .00

Simple Message Recall 0.95 .00

Complex Message Recall 0.93 .00

Delayed

Category Recall 0.98 .00

Brand Recall 0.99 .00

Simple Message Recall 0.95 .00

Complex Message Recall 0.99 .00

Accordingly, it appeared that there were very high correlations between the marks of two markers across all four categories (see Table 5-4). Therefore, the marks under each category were averaged into a single mark and used for further analysis.