Mixed mode surveys refer to surveys based on the combination of various contact and survey methods. They generally aim to improve representativeness by increasing coverage and decreasing non-response rates. The most common and most effective mixes are the combination of online surveys with written questionnaires (CAWI-PAPI) or the combination of online and telephone surveys (CAWI-CATI). When used correctly and with the right conditions, this achieves relevant structural gains and utilization of over 50%.LINK makes use of the following key elements to ensure the success of your mixed mode survey:

• Operation of a professional multi-channel hotline (telephone, email, SMS, chat) for questionnaire deliveries, direct interviews, simple requests for information and support
• Integral data retention in Switzerland and a uniform, in-house survey system
• Advice on determining the appropriate primary method – generally CAWI first – and phased offer of the second survey method (primarily reactive via the hotline during the second phase of an active offer)
• Targeted and method-specific handling of the item non-response option (e.g. “don’t know,” “no answer” etc.)
• Designing questionnaires or checking existing questionnaires by our experts, who check for method effects, as well as content-related aspects, filtering etc. and possible adjustments beforehand

The term “mixed mode” encompasses a wide variety of different combinations of contact and survey methods. Not only are the combinations of methods extremely varied, so are the times and ways in which the targeted individuals are approached: Small variations can quickly have large effects and can positively or negatively influence the goal of increasing representativeness with higher coverage and lower non-response rates. The same applies to the effects of methods that need to be anticipated with mixes of self-completed surveys and interviewer-aided interviews, and that need to be minimized as the situation requires.