Mixed-mode surveys have become a standard at many statistical institutes. However, the introduction of multiple modes in one design goes with challenges to both methodology and logistics. Mode-specific representation and measurement differences become explicit and demand for solutions in data collection design, questionnaire design, and estimation. This is especially true when surveys are repeated and are input to long time series of official statistics. So how can statistical institutes deal with such changes? What are the origins of mode-specific error? And how can they be dealt with? In this book, the authors provide answers to these questions, and much more. Features Concise introduction to all the key elements of mixed-mode survey design and analysis Realistic official statistics examples from three general population surveys Suitable for survey managers and survey statisticians alike An overview of mode-specific representation and measurement errors and how to avoid, reduce and adjust them.