It has been a decade since a landmark piece of work on child well-being measurement based on a summary index was developed in the United States, the Index of Child and Youth Well-Being. Several research studies, both in the U.S. and Europe, followed on from this work. Despite these studies' valuable contribution, scope exists for further improvements at the methodological level. In the present paper we draw the methodological basis for a new, micro-based summary child well-being index in which children's views on their own well-being assume a central role and distinct weights (based on the children's perceptions) to each component that is included in the index are used. Based on 914 pairs of responses of Portuguese children and their carers, the newly proposed index was tested vis-A -vis other methodologies. The econometric estimations show that the significance of all potential well-being determinants (e.g., age, school cycle, mother's and father's level of education) remains the same across the distinct methods of calculation of child well-being indexes. However, the consideration of subjective components (degrees of importance and weights) allowed to evidence that the most relevant determinants of child well-being are the set of variables related to the child's parents, namely education and professional status. In particular, when compared to their counterparts, children whose fathers have higher education degrees reveal an increased overall well-being by around 25 %, whereas children whose fathers are unemployed present a decreased well-being by around 11 %.
