Adaptive survey designs assume that different persons or households can receive different treatments. These designs find their origin in the literature on medical statistics where treatments are varied beforehand over patient groups but also depend on the responses of patients, namely measurements during data collection. This chapter talks about static and dynamic survey designs. Static survey designs are set before data collection starts and do not depend on paradata obtained during data collection. Dynamic survey designs choose between different design features based on observations made by interviewers or data collection staff. A special case of an adaptive survey design is the responsive survey design. Responsive survey designs must identify promising and effective treatments or design features during data collection. Controlled Vocabulary Terms data collection