RELIABILITY ASSESSMENT

The constructs measured in this study are usefulness, trust, subjective norms, enjoyment, site quality, and continuance intention to use. All constructs were measured using multiple-item, fully anchored, seven-point, and Likert scales.

Reliability tests the stability of individual measurement items across replications from the same source of information (Straub, 1989). The initial scientific test, therefore, is to determine the reliability of the research instrument. Before proceeding with any data analysis, all research instruments were tested for their reliability and validity. Cronbach’s α and the corrected item-to-total correlations provide the statistical criteria for any item modifications

or eliminations (Nunnally and Bernstein, 1994). Cronbach’s α is used to examine the reliability of each construct; passing this test is a prerequisite for further analysis. All initial scale items were taken from previously validated measures in IS literature or TAM and ECT research. Scale items were reworded to relate to the e-shopping continuance usage context. Whenever possible, at least three items were included per construct to ensure adequate reliability, as recommended by Nunnally (1978).

The cut-off for acceptable corrected item-to-total correlations is 0.3 (Nunnally and Bernstein, 1994). Any item with negative corrected correlations is eliminated from any further consideration. The Cronbach’s α measures the internal consistency and reflects how each item correlates with other items or with the entire scale; the acceptable cut-off point is 0.8 (Fornell and Larcker, 1981), though a value of greater than 0.7 (Hair et al, 2006) or even 0.6 (Nunnally, 1978) are considered satisfactory. The criteria suggested by Hair et al (2006), Nunnally (1978) and Fornell and Larcker (1981) were applied to determine the adequacy of the reliability coefficients (composite reliability or The Cronbach’s α) obtained for each measure.

The reliability assessment considers the responses to the online shopping survey from Saudi Arabians, which contained 35 items for measuring internal consistency and item correlations. All items used Likert scales.

The Cronbach’s α scores of the variables are high, ranging from 0.928 to 0.961. This is well above the accepted lower limit of 0.7 (Hair et al, 2006). In addition, all item-to-total correlation values are significantly greater than 0.3 (Nunnally and Bernstein, 1994). The Cronbach’s α values in Table 6.19 are all greater than 0.7 (Hair et al., 2006; Bagozzi and Yi, 1988). Furthermore, each variable indicates good reliability. Therefore, the initial reliability assessment indicates that all variables have sufficient reliability. This is a prerequisite for the next analysis stage.

Because social science research often tries to measure intangibles, such as intention, behaviour, satisfaction, enjoyment, and trust, it is hard to know for certain whether items measure variables accurately. Validity indicates the capacity of a test to indicate what is already known (Bannister and Mair, 1968).

As noted in Chapter 5, the face validity measure asks participants if they feel that the questions represented the purpose of the study. Participants in the pilot study phase agreed

that the questions represented the introduced propose of the study. Additionally, content validity assesses constructs taken from existing research. Expert academics confirmed that the questionnaire items represented the study adequately.

TABLE 6.19: SUMMARY OF MEASUREMENT SCALES

Coding Variable / Measurement Item Item-to-Total Correlation

Cronbach’s

α

Total Cronbach’s α 0.967

PU Perceived usefulness 0.945

PU1 The website I use for my online shopping is useful for searching and purchasing.

0.767 PU2 The website I use for my online shopping improves my

performance in searching and purchasing.

0.799 PU3 The website I use for my online shopping enables me to

search and purchase faster.

0.865 PU4 The website I use for my online shopping enhances my

effectiveness in searching and purchasing.

0.879 PU5 The website I use for my online shopping makes it

easier to search for and purchase.

0.877 PU6 The website I use for my online shopping increases my

productivity in searching and purchasing.

0.820

Trust Trust 0.948

TBI1 The website I use for my online shopping is truthful in its dealings with me.

0.860 TBI2 I would characterize the website I use for my Internet

shopping as honest.

0.890 TBI3 The website I use for my online shopping would keep its

commitments.

0.847 TBI4 The website I use for my electronic shopping is sincere

and genuine.

0.899

Enj Perceived Enjoyment 0.819

PE1 Shopping online in this website would be fun for its own sake.

0.613 PE2 Shopping online in this website would make me feel

good.

0.700 PE3 Shopping online in this website would be boring. 0.198 PE4 Shopping online in this website would involve me in the

shopping process.

0.708 PE5 Shopping online in this website would be exciting. 0.760 PE6 Shopping online in this website would be enjoyable. 0.741 PE7 Shopping online in this website would be

uncomfortable.

0.200 PE8 Shopping online in this website would be interesting. 0.687

SQ Perceived Site Quality 0.928

PSQ1 Overall, this website worked very well technically. 0.829 PSQ2 Visually, this website resembled other sites I think

highly of.

0.817 PSQ3 This website was simple to navigate. 0.841 PSQ4 On this website, it was easy to find the information I

wanted.

0.810 PSQ5 This website clearly showed how I could contact or

communicate with online shopping customer service.

SN Subjective Norms 0.945

SN1 Most people who are important to me would think that using the website to shop online is a wise idea.

0.793 SN2 Most people who are important to me would think that

using the website to shop online is a good idea.

0.797 SN3 Most people who are important to me would think I

should use the Internet to shop online.

0.833 SN4 My family who are important to me would think that

using the website to shop online is a wise idea.

0.887 SN5 My family who are important to me would think that

using the Internet to shop online is a good idea.

0.858 SN6 My family who are important to me would think I

should use the website to shop online.

0.824

CIU Continuance Intention of Use 0.961

CIL1 I intend to do more business with the present website. 0.850 CIL2 I would recommend the website I use for my online

shopping to those who seek my advice about such matters.

0.917

CIL3 I would encourage friends and relatives to use the website I use for my online shopping.

0.932 CIL4 I intend to continue to do business with the present

website.

0.915 CIL5 I would post positive messages about the website I use

for my online shopping on some Internet message boards.

0.869

CIL6 I say positive things about the website I use for my online shopping to other people.

0.773