LSAC is collecting a great deal of information on children's development, health and wellbeing. For the purposes of communication, it is useful to provide a summary measure of child functioning, that can then be used in comparisons of different groups (sociodemographic, geographical, etc.) and to track change over time. The LSAC team has developed an Outcome Index for both the infant and 4 year old cohort on the basis of Wave 1 data. This Index bears some similarities to the Vulnerability Index created from the Canadian NLSCY dataset, but attempts to reflect children's strengths as well as their weaknesses, and to improve upon the Canadian scale in its psychometric properties. Unlike sets of indicators which typically include risk factors which are thought to be associated with child functioning (for example, poverty, single-parent household), the Outcome Index includes only direct measures of child functioning. One of the strengths of LSAC is that it is collecting data about all aspects of children's functioning. While these are closely interconnected, they can be considered to encompass the following domains: health and physical development; social and emotional functioning; and learning. Key measures of these domains of functioning are used to create domain scores, which are then combined to create the Outcome Index. Indices of positive as well as negative functioning are being created. This paper will describe the development of the Outcome Index and illustrate some of the ways in which it can be used.