[영문]The Common Assessment Framework is a standard assessment tool to be used by all professionals working with children for assessment and referral. The CAF is hailed as a needs-led, evidence-based tool which will promote uniformity, ensure appropriate ‘early intervention’, reduce referral rates to local authority childrens services and lead to the evolution of ‘a common language’ amongst child welfare professionals. This paper presents findings from a study, funded under the Economic and Social Research Councils e-Society Programme. Our purpose in is not primarily evaluative, rather we illustrate the impacts of CAF as a technology on the everyday professional practices in child welfare. We analyse the descriptive, stylistic and interpretive demands it places on practitioners in child welfare and argue that practitioners make strategic and moral decisions about whether and when to complete a CAF and how to do so. These are based on assessments of their accountabilities, their level of child welfare competence and their domain-specific knowledge, moral judgements and the institutional contexts in which these are played out