[영문]The study describes collaborative involvement of child welfare agencies in Sweden with mandated reporters and analyses the association between socioeconomic and demographic factors as well as collaborative involvement on referral rates. The empirical material consists of data collected on location in 100 Swedish child welfare agencies, augmented with register data. The study shows that: (i) collaboration is common in the child welfare field, (ii) structural factors moderately predict municipal variations in child welfare referrals and (iii) most importantly, that collaboration on the aggregate level seems to serve as a marginal, or even counter-productive, measure in identifying children and adolescents at risk. The results are particularly discussed in the context of policy principles in Swedish child welfare, i.e. collaboration as a statutory requirement for child welfare agencies and the official notion of collaboration as an important means to facilitate early interventions.