This commentary is a response to the article by James Proctor titled “Theory In, Theory Out: NCSE and the ESS Curriculum” (Environ Stud Sci 5(2):218–223, 2015) which critiques the report Interdisciplinary Environmental and Sustainability Education on the Nation’s Campuses 2012: Curriculum Design (Vincent et al. 2013) and its findings related to environmental studies and sciences (ESS) curricula. Our report does not constrain curricular discussion or evolution nor does it encourage a move toward convergence in ESS curricula as Proctor asserts. Instead, the implications are simply that, while there is a wide diversity of interdisciplinary environmental and sustainability (IES) degrees, there are some shared aspects of the identity of the field and broad approaches to curriculum design. The results also reveal that a degree program’s name is not a reliable indicator of curricular content and that newly emerging programs in sustainability and energy fit within the broad ESS paradigm. All of the National Council for Science and the Environment’s (NCSE) Center for Environmental Education Research (CEER) studies and reports are designed to support ongoing discussion by providing relevant information obtained using rigorous research design and statistical analysis techniques. They are not intended to be prescriptive or support the status quo.