Since 2013, DaSy has tracked the status of Part C and Part B 619 state data systems to understand states’ technical assistance needs, provide stakeholders with a national picture of what capacities state data systems have, and to track how those capacities are changing over time. Most recently, in spring of 2021, DaSy collected comprehensive information on Part C and Part B 619 data systems using an online survey developed in coordination with the IDEA Infant and Toddler Coordinators Association for Part C programs and a parallel survey for Part B 619 programs. The Part C and Part B 619 surveys contained many of the same items. (author abstract)