3.3. Ego network analysis
In the control group, 17 members (25.8%) were identified as core members, three members (4.5%) were active, and 46 members (69.7%) were alienated. In the intervention group, 15 members (22.7%) were core members, 33 (50.0%) were active, one member (1.5%) was showed little activity, and 27 members (40.9%) were alienated.The community childcare doctor showed that the ego network (the size value was 17 and 44 in the control and intervention groups, respectively), had the largest number of ties (the ties value was 14 and 128 in the control and intervention groups, respectively), but the smallest density (the density value was 5.15% and 6.77% in the control and intervention groups, respectively), which demonstrated that the community childcare doctor was positioned in a core situation, mainly received (rather than sent) parents' messages, and was responsible for answering parents' questions. In addition, the two-step reach of the community childcare doctor was 29.23% and 65.33% in the control and intervention group, respectively, which was relatively high in all ego networks, and which demonstrates that the community childcare doctor had an ability to deliver information regarding the safety of children aged 0–3.For the other parents, in the control group four parents (parent 1104, parent 1128, parent 1145 and parent 1200) had sizes of 6, 5, 4, and 3, respectively; the values for their ties were 8, 7, 4, and 2, respectively, their density values were 26.67%, 35.00%, 33.33%, and 33.33%, respectively; and their two-step reach values were 32.31%, 29.23%, 32.31%, and 26.15%, respectively. This demonstrated that they played an active role, not only asking questions of the community childcare doctor, but also answering other parents' questions or providing suggestions. Additionally, they, as core WeChat group members, participated in most interactions.In the intervention group, 14 parents (parent 1119, parent 1074, parent 1196, parent 1004, parent 1146, parent 1222, parent 1058, parent 1241, parent 1056, parent 1080, parent 1109, parent 1189, parent 1218 and parent 1174) showed sizes of 19, 17, 15, 13, 12, 11, 11, 10, 10, 9, 8, 8, 7, and 7, respectively; the values for their ties were 95, 95, 82, 56, 45, 41, 61, 46, 49, 48, 35, 12, 28, and 19, respectively; their density values were 27.78%, 34.93%, 39.05%, 35.90%, 34.09%, 37.27%, 55.45%, 51.11%, 54.44%, 66.67%, 62.50%, 21.43%, 66.67%, and 45.24%, respectively, and their two-step reach values were 64.00%, 64.00%, 65.33%, 64.00%, 64.00%, 64.00%, 62.67%, 64.00%, 61.33%, 61.33%, 61.33%, 61.33%, 62.67%, and 37.33%, respectively. This suggests that these parents played an important role in helping the community childcare doctor answer some of the other parents' questions.Compared to the control group, the intervention group was more active and featured more parents who may have played a role in answering questions, which shaped its post-intervention ego network (