Declining response rates force survey researchers to implement surveying strategies that would motivate target persons to cooperate. Incentives have often proved to be a viable approach to address this issue. They have been increasingly used also in web surveys, which are relatively cheaper, compared to other modes but at the same time suffer from generally lower response rates. Since the problems like noncoverage and lack of sampling frames still make web surveys largely inappropriate for surveying general populations, the possibility of their integration into mixed-mode designs has become one of the central questions of survey methodology. This introduced a new area also for methodological research