This report presents preliminary findings for the analysis of the eligibility redetermination period extension from six months to 12 months in Illinois. We describe the integrated database of child subsidy payment records that serves as the primary data source for the study and discuss the strengths and limitations of the data. Developing the child care longitudinal database (CCALD) database was a primary activity of the first grant year. We present analyses that identify the study sample, which draw from a data system change in 2014 that resulted in a natural experiment of certain cases receiving automatic extensions to 12 or more months, providing an opportunity to test the effects of an extended eligibility period. We examine descriptive statistics for the study sample. The report ends with a discussion of next steps for the analyses in the next grant year. (author abstract)