The team member questionnaire included control variables as well as a series of social network questions to measure friendship, advice, and hindrance networks in teams. Rosters of all team members including the team leader (Marsden, 1990) in alphabetical order asked participants to answer those questions about each person of their team (excluding themselves). All network measures were calculated using UCINET (version 6.497; Borgatti et al., 2002).
2.3.2.1 Advice and Friendship Leader Centrality in Multiplex Team Ties Following Perry-Smith (2006), friendship relations were measured with team members’ responses to a single item, “How close are you with each person?” (1 = “acquaintance,” 2 = “distant colleague,” 3 = “friendly colleague,” 4 = “good friends,” 5 = “very close friends”), over their leaders. To assess
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advice relations, team members responded over their leaders to a single item by Chua, Ingram and Morris (2008), “Please indicate the extent to which you obtain information or advice from this person to get tasks done” (from 1= “very little extent” to 5 =”Very great extent”).
In line with our theoretical rationale, leaders often shared friendship and advice ties with the same team member. We therefore computed multiplex ties following Prell (2012). As a first step, we computed individual friendship and advice simplex tie matrixes. Following Perry-Smith (2006), we coded a friendship tie as “1”, if members indicated to be “good friends” or “very close friends” with a leader. The categories “friendly colleagues”, “acquaintance”, and “distant colleague” were coded “0”. For the advice network, we coded “great extent” and “very great extent” as “1”, and “very little extent”, “little extent”, and “some extent” as “0”. The resulting matrixes of simplex relations were then combined into one multiplex tie matrix. If the two simplex matrixes showed the presence of advice and friendship ties, this was coded as “1” in the multiplex matrix. If either a friendship or advice tie (or no tie) were present, this was coded as “0” in the multiplex matrix. Although the use of multi-item measures to improve reliability is desirable, it is acceptable in network studies to limit network data collection to single-item measures in order to reduce participant fatigue and resulting poor response rates (e.g., Marsden, 1990). The final measure of leader centrality was calculated as leaders’ normalized in-degree centrality (Sparrowe et al., 2001) within this team multiplex matrix.
2.3.2.2 Hindrance and Friendship Density in Teams
We measured friendship density based on team members’ (excluding the leader) responses over all other team members on Perry-Smith’s (2006) item described earlier. We measured hindrance networks with Baldwin et al.’s (1997) measure of adversarial relationships, asking team members to what extent the relationship with other team members was difficult. The scale ranged from 1 (very little extent) to 5 (very great extent). Because we
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had valued data, measures of intrateam density were computed as the sum of the values of all ties divided by the number of possible ties (Hanneman & Riddle, 2005), thereby reflecting the average strength of ties across all possible ties within teams.
2.3.2.3 Managerial Ratings of Team Performance
Line managers assessed team performance (both Times 1 and 2) as the extent to which the team met its performance standards of quality, quantity, timeliness, implementation, and had a reputation for work excellence within the organization, based on Vinokur-Kaplan’s (1995) 5- item scale ranging from 1 (not at all) to 5 (completely). This theory-based measure was chosen because it is generic enough to apply to a variety of teams in the service sector, thereby enabling comparisons of the extent to which various teams meet their respective performance standards. An example item is, “To what extent do you feel that this team met the standards of quality expected by your organization?” Cronbach’s alpha was .74 (Time 1) and .91 (Time 2).
2.3.2.4 Control Variables
We controlled for a number of variables that could present potential confounds or alternative explanations for our findings. We thus controlled for team size, task complexity, clarity of team boundaries, team stability, and team interdependence. In order to assess longitudinal change in team performance after two years, we controlled for team performance Time 1, using the measure described above. Because one line manager oversaw three teams, we created a dummy code for each of these teams in order to control for possible effects of non-independence (Bliese, 2000).
Clarity of team boundaries, team stability, and team interdependence were assessed with Wageman et al.’s (2005) measures described in the “sample and procedures” section above. Cronbach’s alpha was .78 for clarity of team boundaries, and .82 for team stability. Task complexity was
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measured with three items from Dean and Snell (1991). The first two items were measured on a scale ranging from 1 (very little) to 7 (a great deal). The third item was measured on a scale ranging from 1 (not at all) to 7 (very complicated). Cronbach’s alpha was .82.
As the focus of this study is on the importance of leader multiplex ties, we wanted to demonstrate their incremental effects above and beyond member multiplex ties. Member multiplex ties were computed in analogous fashion to leader multiplex ties, using the same simplex friendship (Perry-Smith, 2006) and advice (Chua et al., 2008) network measures introduced above, this time completed by team members (excluding the leader). Following the same procedure as for leader multiplex ties, we first computed simplex tie matrixes, and then combined them into one multiplex matrix. Based on this multiplex matrix, we calculated the final measure intrateam density measure (Hanneman & Riddle, 2005), reflecting the number of multiplex ties across all possible multiplex ties within teams.