Item analysis and reliability estimation

socializing (21.5%), games and entertainment (13.7%), and information services (13.7%), to positioning and navigation (12.7%).

Table 6. Mobile service use experience descriptive data

Measure Option Frequency Rate (%)

Product types Tangible products 90 15.6

Intangible products 488 84.4

Mobile service use experience Messaging/ voice calls 159 27.5 Positioning and navigation 71 12.3 Value-added service

(e.g. music/ magazine subscriptions)

32 5.5 Mobile trading services

(e.g. Shopping and financial services)

29 5.0

Mobile socializing 124 21.5

Games and entertainment 79 13.7

Information services

(e.g. news, stock quotes, weather, etc.) 79 13.7

Other 5 0.9

4.2 Item analysis and reliability estimation

The 45-item and 43-item instruments were refined by analyzing the pooled data which were collected from experienced users across tangible and intangible products shopping and on different types of mobile handheld devices. Because the primary purpose of this study was to develop a reliable instrument that accurately measures M-S-QUAL for various types of mobile service, it was considered appropriate to pool the sample data.

The first step in purifying the instrument was to delete items based on Cronbach’s  and corrected item-total correlations (Cronbach, 1951). Next, prior to identifying its underlying dimensions using exploratory factor analysis, based on the assumption that all items in the M-SQ instrument share a common core, the coefficient  and corrected item-total correlations for the 45-item/43-item M-SQ instrument of tangible/intangible products scope were calculated. Initially, the value of the Cronbach's  ranged from 0.83 to 0.97 across nine constructs of both tangible and intangible products transactions (Table 7). We then used the item’s corrected item-total correlation of each item as the criterion for deciding whether to delete the item. Although the

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corrected item-total correlation value recommended is greater than 0.5 (Churchill, 1979), we chose a stricter criterion of 0.7. If the corrected item-total correlation value was below 0.7, the item was deleted.

Table 7. Item analysis – reliability

Construct Tangible products Intangible products Number of items Cronbach's  Number of items Cronbach's 

Efficiency 4 0.96 4 0.94

System available 3 0.92 3 0.94

Content 7 0.96 7 0.94

Privacy 3 0.93 3 0.93

Contact 7 0.97 7 0.96

Billing 7 0.96 7 0.95

Fulfillment 7 0.95 5 0.90

Responsiveness 4 0.93 4 0.93

Compensation 3 0.83 3 0.92

We then recalculated the Cronbach's  values for the remaining items, examined the new corrected item-total correlations, and deleted more items if necessary. The cut-off values were considered high enough to ensure that the items retained were adequate measures of the M-S-QUAL construct. Three items were eliminated at this stage, resulting in a 44-item scale for measuring tangible products M-S-QUAL and a 41-item scale for measuring intangible products M-S-QUAL (as shown in Table 8).

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Table 8. Item analysis – corrected item- total correlation

Item code

Item Corrected item-to-total

correlation Tangible products

Intangible products Ef_1 It enables me to complete a transaction quickly. 0.91 0.89 Ef_2 It loads its pages fast. 0.90 0.87 Ef_3 This site is simple to use. 0.88 0.80 Ef_4 This site enables me to get on to it quickly. 0.92 0.88 SA_1 This site launches and runs right away. 0.86 0.85 SA_2 This site does not crash. 0.80 0.87 SA_3 Pages at this site do not freeze after I enter my order information. 0.85 0.87 Ctt_1 The content of the mobile web site is concise. 0.87 0.82 Ctt_2 The content of the mobile web site is accurate. 0.88 0.84 Ctt_3 This web site provides complete content. 0.85 0.84 Ctt_4 This web site provides appropriate content. 0.86 0.87 Ctt_5 This web site provides important content. 0.84 0.86 Ctt_6 This web site provides fashionable content. 0.81 0.72 Ctt_7 This web site provides regularly updated content. 0.86 0.75 Pr_1 It protects information about my web-shopping behavior. 0.87 0.85 Pr_2 It does not share my personal information with other sites. 0.89 0.88 Pr_3 This site protects information about my credit card. 0.80 0.83 Con_1 Friendliness when reporting complaint. 0.91 0.86 Con_2 Service agents provide consistent advice. 0.90 0.87 Con_3 Customer service representative is polite. 0.89 0.87 Con_4 Call center personnel are able to help with problems. 0.86 0.89 Con_5 It offers the ability to speak to a live person if there is a problem. 0.90 0.86 Con_6 This site provides a telephone number to reach the company. 0.89 0.86 Con_7 This site has customer service representatives available online. 0.85 0.81 Bi_1 The mobile web site provides convenient payment procedures. 0.85 0.81 Bi_2 Provides accurate billing. 0.89 0.86 Bi_3 Makes it easy to understand and resolve billing issues. 0.84 0.83 Bi_4 Resolves billing issues quickly. 0.92 0.88 Bi_5 Variety of price schedules 0.83 0.83 Bi_6 Possibility of freely choosing price schedules 0.80 0.82 Bi_7 When the download was completed, the trading information was

sent back in a timely fashion.

0.80 0.80 Ful_p_1 It delivers orders when promised. 0.85 -

Ful_p_2 This site makes items available for delivery within a suitable timeframe.

0.90 -

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Item Corrected item-to-total

correlation Ful_p_6 It is truthful about its offerings. 0.80 - Ful_p_7 It makes accurate promises about delivery of products. 0.82 - Re_p_1 It provides me with convenient options for returning items. 0.84 - Re_p_2 This site handles product returns well. 0.85 - Re_p_3 This site offers a meaningful guarantee. 0.88 - Re_p_4 It tells me what to do if my transaction is not processed. 0.75 - Com_p_1 This site compensates me for problems it creates. 0.74 - Com_p_2 It compensates me when what I ordered doesn’t arrive on time. 0.79 - Ful_v_1 It delivers orders when promised. - 0.76 Ful_v_2 This site makes items available for delivery within a suitable

timeframe.

- 0.83 Ful_v_3 It quickly delivers what I order. - 0.80

Ful_v_4 It has in stock the items the company claims to have. - 0.83 Re_v_1 It provides me with convenient options for returning items. - 0.87 Re_v_2 This site handles product returns well. - 0.89 Re_v_3 This site offers a meaningful guarantee. - 0.89 Com_v_1 This site compensates me for problems it creates. - 0.87 Com_v_2 It compensates me when what I ordered doesn’t arrive on time. - 0.87 Com_v_3 It picks up items I want to return from my home or business. - 0.76