Families are significantly affected by decisions made in the child protection context, yet decision outcomes differ even when cases are similar. Understanding the concepts, practices and processes of differentiation that push some cases over the threshold of key decision points, but not other similar cases, is crucial. Drawing on interviews and focus groups with child protection social workers from three site offices in Aotearoa New Zealand (interviews, n = 26; focus groups, n = 25) and using thematic analysis, this study identified the case, internal organisational, inter-site organisational and external elements that contributed to threshold decisions. Case factors such as children’s age, abuse type and chronicity recorded family history and perceptions of family compliance interacted with internal organisational processes and practices, social negotiations and hierarchical power differences to produce decision outcomes. Inter-site differences in decision thresholds resulted from differences in site managers’ perceptions of acceptable case type, site workloads, resources, size and cultural commitment to family preservation. External demographic inequalities were perceived as causing differing levels of site workload. This ‘networked decision-making’ process is theorised drawing on an extended version of the decision-making ecology (DME), by using qualitative methods to examine interactions between the DME elements and their relationship with risk regimes.