# R-indexes for the comparison of different fieldwork strategies and data collection modes

Many survey organisations focus on the response rate as being the quality indicator for the impact of non-response bias. However, it is not true in general that higher response rates imply smaller non-response bias. We introduce a number of concepts and indicators to assess the similarity between the response and sample of a survey. Such quality indicators may serve as counterparts to survey response rates and are primarily directed at evaluating the non-response composition.