Table 1.

Glossary of main terms and their relation to the research questions

Term	Definition
Efficiency	Criterion of assessment which describes to which degree a response is suitable to achieve an objective in a certain way. The definition of an ecologically efficient soil sealing management approach is provided in Table 2
Response	Specific instrument which aims to steer soil sealing (e.g., a specific law such as the building code). This paper assesses the efficiency of ecological sustainable responses
Strategy	Strategy is understood as the sum of responses addressing the same types of steering. Within this study legal-planning, informal-planning, economic-fiscal, co-operative and informational strategies are investigated. The efficiency assessment of strategies is based on the assessment of responses which are assigned to strategies (see Fig. 1)
Sub-targets	Sub-targets define what has to be steered spatially in the course of a holistic soil sealing management approach. These targets relate to steering urban green (open land such as forests and agricultural land, recreational areas), gray (built-up areas and artificial material) and soil (land and substrate). Urban green and gray can be steered quantitatively (reduction of new sealing and land take, protection of green areas), qualitatively (promotion of internal development and space efficient building forms, protection of green areas with high ecological performance). Moreover, existing sealed areas can be compensated by de-sealing or greening roofs (see also Fig. 1). The efficiency assessment of sub-targets is based on the assessment of responses which are assigned to the sub-targets
Actors	Actors of soil sealing management refer to administrative units and communities responsible for developing and implementing strategies in the course of a holistic soil sealing management. The responses selected are assigned to groups of actors of different management scales to prove who is responsible for soil sealing management and to which degree (see Fig. 1)