Fig. 6

Number of articles by for (A) study type, (B) study comparator type, (C) study geographic scale, and (D) whether study reported cost. Some articles contained more than one study type or comparator, so articles can appear in more than one category within each panel. Comparators are: “structure type” compares different types of built structure interventions, “presence v. absence” compares the presence or absence of built structure; “temporal” tracks built structures over time, “none” is no comparator, “spatial” compares built structures at different sites or from different projects, “built v. green” compares a built structure intervention to a green or natural structure, “before v. after” compares before built structure construction to after, “habitat type” compares built structures in different habitat types, “built v. gray” compares a built structure to a fully gray intervention