Administrative Supplement to Support Public Availability of Legacy COG Clinical Trial Data The NCTN/NCORP Data Archive serves as a repository of clinical trial data from phase 3 studies funded by the NCI and published after 2015. However, some clinical trials are excluded from mandatory reporting to the NCI Data Archive, including phase 1 or 2 studies and older phase 3 studies with primary publication dates prior to 2015. Some of these datasets may be useful for secondary analyses by other investigators if patient-level data were made available publicly. For example, a well annotated clinical trial dataset from phase 1 or 2 studies could be used as an external control for the purpose of FDA approval of an agent evaluated in a single arm study without a concurrent control arm. Another example is the pooling of outcome data for an uncommon tumor histology from multiple phase 2 studies to guide the design of a future study. To increase the number of study datasets that are available for public use, COG is requesting an administrative supplement to fund the generation of selected legacy clinical trial datasets.