*5.10. Qualifiers*

We recognize that there are likely peer reviewed articles addressing urban greenways that this review did not capture. For example, some greenway studies may have been conducted in an urban context but they did not use the term "urban greenway" or "urban greenways" in the title, abstract, or keywords; and there may be studies that were not included in the databases we searched. Thus, this paper should not be read as a comprehensive assessment of any and all peer reviewed studies on greenways in an urban context. On the other hand, urban ecology has shown that the urban context can have different meanings, especially in an urbanizing world where the ecological footprint of cities can extend to global scales [99–101]. Thus, a constructive attribute of this study is that it focuses explicitly on studies addressing landscapes described as urban greenway(s) in the title, abstract, or keywords, and in so doing, provides a focused snapshot of this literature. An additional caveat is that distilling research into discrete categories and sub-coding these categories into discrete classes, can be a subjective and reductionistic act, both of which have inherent problems. Subjective classification is based on the assessors' interpretation, which can introduce unconscious bias and error [102]. Reductionism can, in turn, oversimplify complex relationships [103,104]. With these caveats in mind, categorization and classification can be helpful when seeking to advance understanding of a complex topic or phenomenon.
