HW 6: Measurement & Reliability

Background

A group can be defined as two or more interdependent individuals. Typically, these individuals must interact socially in order to accomplish a common goal (Jex, 2002). If implemented correctly, groups can improve decision making and problem solving and enhance performance and productivity. There are several different ways to evaluate group effectiveness, including group outputs, member satisfaction, longevity, and potential for innovation (Nahavandi & Malekzadeh, 1999). One area that often receives attention in the popular press is group synergy. Group synergy occurs when the performance of a group is greater or better than what the combined performance of the group members would have been had they worked alone.

There are many factors that influence group performance, such as the structure of the group, the characteristics of the members, and the available resources (Hackman, 1987). One factor that has been evaluated on several occasions is group member agreeableness. Agreeableness is a personality variable that indicates the degree to which an individual strives to be accommodating in a social situation (McCrae & Costa, 1997). Research has shown that group members' agreeableness can affect group performance (e.g., Halfill et al., 2005). However, the optimum level of agreeableness for group performance likely depends on the situation or task. Although agreeable members can improve group harmony because these individuals try to be cooperative, performance can be hurt by the fact that agreeable individuals have a difficult time saying "no" and do not like to question the decisions of others. On the other hand, less agreeable group members are more likely to be assertive and better at making difficult decisions, which can improve group performance.

Data for this homework are from a study that explored the effects of type of decision making and group agreeableness on decision accuracy in an ill-defined decision-making task. Participants had to decide which items in their possession were most important for survival if they were lost in the Amazon jungle. They ranked 15 items from most important to least important. There were two decision-making conditions in this study. First, each participant ranked the Amazon survival items individually (the "individual score"). Second, they were placed into groups of 3 or 4 and each group generated a consensus ranking of the survival items (the "group score"). Scoring was based on the comparison of individual and group rankings with the ranking providing by a group of Amazon survival experts. The final score is the total absolute value difference between the individual participant or group rankings and the expert ranking. Thus, a lower score represents better accuracy as the lower the score the more closely the ranking matched that of the experts(the best possible score would be zero if a participant's ranking perfectly matched the expert ranking).

The second independent variable was group-level agreeableness. Each participant individually completed a 10-item assessment of their agreeableness personality twice, three days apart (time 1 and time 2). Each participant received a score by averaging their responses to the 10 questions. High agreeable and low agreeable groups were then created based on the individual participant's agreeableness scores (in other words, a high agreeable group is a group where all members had high agreeableness scores and a low agreeable group is a group where all members had low agreeableness scores).

References

Hackman, J. R. (1987). The design of work teams. In J. W. Lorsch (Ed.), Handbook of organizational behavior (pp. 315- 342). Englewood Cliffs, NJ: Prentice Hall.

Halfhill, T., Nielsen, T. M., Sundstrom, E., & Weibaecher, A. (2005). Group Personality Composition and Performance in Military Service Teams. Military Psychology, 17, 41-54.

Jex, S. M. (2002). Organizational psychology: A scientist-practitioner approach. New York: Wiley.

McCrae, R. R., & Costa, P. T., Jr. (1997). Personality trait structure as a human universal. American Psychologist, 52, 509-516.

Nahavandi, A., & Malekzadeh, A. R. (1999). Organizational behavior: The person-organization fit. Englewood Cliffs, NJ: Prentice Hall.

HW 3: Measurement & Reliability

Question #1. A single participant's Amazon survival performance was measured by having them rank 15 survival items from most important to least important. This ranking reflects what scale of measurement

a. nominal b. ordinal c. interval d. ratio

Question #2. Was the agreeableness personality measure a self-report measure, an observational measure, or a physiological measure

Question #3. The reliability of the agreeableness measure was computed by correlating participants' total score at time 1 with their total score at time 2. This correlation coefficient was found to be .91. What reliability method was used to compute this estimate:

(a) test-retest (b) alternative forms (c) split-half (d) internal consistency?

Question #4. In general, what can you conclude about the reliability of this "agreeableness" measure based on the .91 correlation that was found between time 1 and time 2 scores?

Question #5. Using the synergy data on the next page, compute the average individual score for each group and then count the number of groups that had a better (lower) group score than their average individual score. Report each group's average individual score on the synergy data sheet on the next page and answer the question below

Number of groups with a better (lower) group score than the average individual scores of their members: _______

Question #6. Based on the result you reported for question #6, was there evidence for group synergy? how you know using the background information provided.

Question 7. Compute the average group score for the high agreeable groups and the average group score for the low agreeable groups and report them below

High agreeable average group score: __________ Low agreeable average group score: __________

Question 8. Based on the results you reported for question #8, what can we conclude about the relationship between group member agreeableness and group performance

Group	Group Agreeableness	Individual Scores	Group Score
Group 1	Low	68	54
52
48
Average:
Group 2	High	52	44
68
58
50
Average:
Group 3	High	78	76
68
50
60
Average:
Group 4	Low	46	38
46
50
46
Average:
Group 5	High	62	54
		58
		66
		58
		Average:
Group 6	Low	62	52
46
54
Average:
Group 7	High	62	54
44
52
74
Average:
Group 8	Low	74	74
70
52
64
Average:
Group 9	High	54	56
64
52
70
Average:
Group 10	Low	52	60
58
58
Average: