Technological advances and increasing access to telephone and the internet mean that it is now possible for people to complete surveys by phone or online rather than face-to-face with an interviewer present. As budgets tighten and the benefits of using other modes (such as speed and flexibility) become more apparent, there has been a debate about whether it is better to use alternatives to face-to-face surveys either exclusively or in combination with in-person interviews. This chapter summarises findings from research conducted under the auspices of the European Social Survey (ESS) over the past 12 years to evaluate the potential effects of mixed-mode data collection on its own cross-national survey estimates
