Leedy and Ormrod (2005) argue that validity of a measurement instrument is the extent to which the instrument measures what it is supposed to measure. It takes different forms, each of which is important in different situations:
Face validity is the extent to which, on the surface, an instrument looks like it is measuring a particular characteristic;
Content validity is the extent to which a measurement instrument is a representative sample of the content area being measured;
Criterion validity is the extent to which the results of an assessment instrument correlate with another, presumably related measure; and
Constructive validity is the extent to which an instrument measures a characteristic that cannot be directly observed but must instead be inferred from patterns in people’s behavior.
The design of the research instrument is expected to contribute to the achievement of validity in the instrument. This is accomplished through the use of five point Lickert scale questions. Assurance in the validity of the results is further reinforced through the delimitation of the research and the consistency of the results received across the respondent sample (Oulton, 1995, p.59 quoted in Doolabh, 2007, p.). Hence the questionnaire was first distributed to a test group and the results proved to be valid.
Leedy and Ormrod (2005) further state that the reliability of a measurement instrument is the extent to which it yields consistent results when the characteristic being measured has not changed.
The Cronbach’s alpha was used as a reliability test. The following tables and figures depict the results of the survey questionnaire.
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Table 4.2: Guidelines for using the Cronbach’s alpha
Cronbach's alpha Internal consistency
α ≥ 0.9 Excellent (High-Stakes testing) 0.7 ≤ α < 0.9 Good (Low-Stakes testing) 0.6 ≤ α < 0.7 Acceptable
0.5 ≤ α < 0.6 Poor
α < 0.5 Unacceptable
Source: Cortina (1993)
Table 4,3: Reliability and average inter-item correlation (Team characteristics)
Domains Mean values Standard deviation Cronbach’s alpha Average inter-item correlation TEAM CHARACTERISTICS* 4.27 0.86 0.66 0.14 Team cohesion 4.04 1.12 0.85 0.68 Task dependence 4.51 0.66 0.64 0.39 Outcome dependence 4.26 0.83 0.82 0.61 Shared leadership* 3.22 1.26 0.16 0.05 Mutual accountability 4.27 0.82 0.60 0.34
*Indicates areas of change
The asterisks in table 4.3 indicate changes that needed to be made in the further analysis of the study.
Table 4.3 depicts the Cronbach’s alpha (0.66) for team characteristics data and a very low average inter-item correlation of 0.14. When the Cronbach’s alpha is below 0.7 is considered as being at an acceptable level which indicates the tested domain has low internal reliability, then the items in this domain do not measure the construct with high reliability (see table 4.2). The low inter-item correlation indicates that the questions in the team characteristics questionnaire were not correlated and measured different aspects of team characteristics. The team cohesion domain had the highest Cronbach alpha (0.85) and the highest inter-item correlation (0.68) of all the three domains in the
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team EI questionnaire. The shared leadership domain had the lowest Cronbach’s alpha of 0.16 which is an unacceptable value for the Cronbach’s alpha and the domain was subsequently deleted from the analysis.
Deleting certain questions in the shared leadership domain would have not improved the domain’s reliability; hence the entire domain was removed. The highest possible Cronbach’s alpha in this domain was 0.40 which is still at an unacceptable level for the Cronbach’s alpha (see table 4.2). Questions 10 to 12 which measured the shared leadership domain were deleted. The team characteristics Cronbach’s alpha then decreased from 0.66 from the previous 0.63 and the inter-item correlation improved from 0.14 to 0.16. The decrease in the Cronbach’s alpha was insignificant since the alpha remained within the acceptable level.
Table 4.4: Reliability and average inter-item correlation (group decision making) Domains Mean values Standard deviation Cronbach’s alpha Average inter- item correlation
GROUP DECISION MAKING* 3.76 0.95 0.81 0.27
Participation in decision making 3.73 1.00 0.81 0.48 Team decision making process* 3.83 0.95 0.13 0.05
Team decision effectiveness 3.96 0.89 0.77 0.47
*Indicates areas of change
Table 4.4 indicates a high Cronbach’s alpha for team decision making of 0.81. The participation in decision making domain had the highest Cronbach’s alpha of 0.81 and the highest inter-item correlation (0.48) of all the three domains in the team decision making questionnaire. The team decision making domain had the lowest Cronbach’s alpha of 0.13. The questions in this section did not relate to each other. The team decision making process domain was subsequently deleted from the analysis due its unacceptable level for the Cronbach’s alpha.
Deleting certain questions in the team decision making process domain would have not improved its reliability; hence the entire domain was removed. The highest possible
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Cronbach’s alpha for this domain was 0.47 which is still an unacceptable level for the Cronbach’s alpha. Questions 6 to 12 which measured the team decision making process were deleted and the group decision Cronbach’s alpha then increased from 0.81 to 0.84 and the average inter-item correlation improved to 0.41 from the previous 0.27.
Table 4.5: Reliability and average inter-item correlation (Team EI)
Domains Mean values Standard deviation Cronbach’s alpha Average inter- item correlation TEAM EI 3.95 0.89 0.88 0.30
Individual level norms 3.96 0.91 0.64 0.26
Group awareness of members 4.14 0.69 0.73 0.58
Group management of
members 3.88 1.00 0.78 0.52
Group level norms 4.03 0.85 0.76 0.30
Group self-awareness 4.13 0.85 0.65 0.48
Group self-management 3.99 0.82 0.61 0.24
Cross-boundary level norms 3.77 1.04 0.78 0.50
Group social awareness 3.81 0.84 0.73 0.39
Group self-management 3.72 1.20 0.93 0.88
Table 5.5 indicates a high Cronbach’s alpha for team EI data of 0.88. When the Cronbach’s alpha is high it means that there is higher internal reliability and the items in the domain measure the construct more reliably. The cross-boundary norms domain had the highest Cronbach alpha (0.78) and the highest inter-item correlation (0.5) of all the three domains in the team EI questionnaire.
The questions in the team emotional intelligence section were better formulated than the questions in the team decision making section since the team EI survey results were more reliable than the team characteristics survey results, the Cronbach’s alpha for team decision making was 0.63 compared to 0.88 for team EI. The team characteristics questionnaire results had the lowest Cronbach’s alpha value of 0.63.
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4.6 DATA SELECTION, COLLECTION AND RESPONSE RATE