# Table 1 Network diagnostics tool

Metric Threshold Description Rationale Teaching methods thought to improve network structure
Isolates Value should be equal to 0 A person not connected to anyone. We want everyone to be connected to at least one other person in the group. Connections are required for behavior transmission. Interventionist should make sure the isolates do not feel excluded. 1. Interventionist is instructed to pair isolates with highly connected group members in small group activities in session.
2. Interventionist is instructed to call on isolates first to answer questions in session with the goal of not letting them fade into the background. Interventionist to refer back to what the isolate said to show their input is valued.
3. Interventionist is instructed to catch the isolate alone (if possible), and to check in with her to let her know we care and ask how GROW is going for her, without putting her on the spot publically.
Degree Value should be greater than 1 The number of ties coming from each person and going to each person. As an extension of isolates, we also want to know how well connected each person is, whether they have links coming from them and going to others. 1. Interventionist is instructed to pair highly connected group members with others in small group activities in session.
Reciprocity Values should be >0.50; (Examine Reciprocity and Reciprocity Non Nulls) d The extent to which ties are reciprocated. If reciprocity is low, existing ties are weak. Transmission of behavior is more likely with strong ties. 1. Interventionist is instructed to pair non-reciprocated links: If A sends a tie to B, but B does not send a tie to A, then Interventionist will pair A and B in small group activities in session.
Components/ subgroups Value should be equal to 0 The presence of disconnected groups in the networks. The presence of components indicates a splintering of the group which might indicate fractions. Interventionist should consider building bridges between fractions/sub-groups. 1. Interventionist is instructed to pair members from different subgroups in small group activities in session (create bridges).
2. Interventionist is instructed to make sure small groups do not split along these lines. If they do, interventionist will reassign members.
Density Value should be >0.15 d but <0.50[3] The extent to which members are connected: number of ties present divided by number of possible ties. If density is too low, the intervention is not building connections. Connections are required for behavior transmission. Interventionist should consider including activities that create more connectivity in the group. 1. Interventionist is instructed to begin each session with an interactive, personalized, community-building ice breaker.
2. Interventionist is instructed to uses a beach ball (“talking stick”) to give each participant the opportunity to be part of the conversation.
3. Interventionist is instructed to helps group establish a stronger group identity: At each session, the facilitator will emphasize (a) the larger GROW family as a support network with a shared mission of improving health; (b) that there needs to be balance in what people put in and get out of the group; and that the more families invest in each other, the more they can get from the group; (c) that all parents need and deserve support in the face of our obesogenic environment, and (d) that this is the most dedicated group of parents committed to the issue of pediatric obesity prevention.
4. The interventionist is instructed to spend 15 minutes so that each member is offered the opportunity to share some relevant aspect of their lives and expectations (personal information). The interventionist gives instruction on the technique of mutual invitation process to structure such sharing.
5. Interventionist facilitates making and meeting a shared common goal.
Centralization Values should be <0.25d (Examine relative values on degree, closeness, betweenness to identify central nodes.) The extent to which the network is focused on one or a few people. An overly centralized network indicates that one person occupies a position of critical importance in the network (i.e., has more social power). Interventionist should either work to decentralize the network, giving others important roles, or work with that central person to make sure they support the intervention. 1. Interventionist is instructed not to let the central node start conversations, be the first person to answer a question, lead goal review, or lead group activity. If a central person asks to lead a group activity, the interventionist redirects so that member on the periphery can take on that role.
2. Interventionist is instructed to avoid pairing central nodes with isolates.
Transitivity e Values should be >0.3d[22] The extent to which two of a person’s friends are friends with each other. Transitivity provides a measure of cohesion in a network. We expect relationships to become transitive; if this is too low it might indicate a hierarchical structure in the network. Interventionist should bring triads together. 1. Interventionist is instructed to bring triads together in activities in session. If A is friends with B and C, Interventionist will connect B and C.
Cohesion e (average of inverse distances) Values should be <0.50 (±.25) e The extent to which individuals in the group are directly connected. The path between two people is the length of the path connecting them. We want higher values which indicate greater group cohesion to facilitate the transmission of behavior. Cohesion is a mediator of group formation and maintenance. 1. Interventionist is instructed to challenge the group to make and meet a shared common goal (weekly wellness challenge: 15 minutes of walking per day). Group will track their minutes during the week and total the group’s minutes to see combined efforts next session. Group will track success each session, increase daily goal in subsequent sessions.
1. This table describes the network diagnostic metrics and thresholds used, why they were selected, along with the corresponding “menu of teaching methods” that can be provided to group leaders to increase group cohesion.
2. d Threshold reflects expert recommendation.
3. e Threshold is a guess and given a wide confidence interval.