Any project that receives Federal funding is required by the National Environmental Policy Act (NEPA) of 1970 to perform an alternatives analysis. This is to make sure the alternative selected is most advantageous when considering all potential environmental and social impacts. There are different tiers of evaluation depending on the size and scope of the project. Due to the size and scope of the Purple Line it required an Environmental Impact Statement (EIS) which has multiple stages including a draft (DEIS) which gets put out for public and formal agency review and then the final (FEIS), which is also published for public review. The final step is that the EIS gets approved by way of the Record of Decision (ROD). Before any Federal funding can be received, the ROD must be in place.