Mixed mode surveys combine the use of telephone, mail, Web, and/or face-to-face interview procedures to collect data for a single survey project. Each basic survey method has certain inherent limitations, therefore we find that leading-edge research firms are designing and implementing mixed mode surveys with increasing frequency. The joint use of these methods allows NuStats to mitigate, if not overcome, certain limitations of individual methods. The goal of mixed mode surveys is to obtain data sets of better quality at lower costs than can be produced by any single method.

Why Use Mixed Mode Surveys? We highlight three key reasons:

There is an industry-wide concern that survey participation rates are lower than in the past. Previous research has shown that people prefer a variety of survey modes as a means of responding to the survey request. The mixed mode design provides an opportunity for respondents to choose or switch methods. Some people who refuse one mode may respond to another. Offering respondents their choice of mode (telephone, mail, face-to-face, or Web) will increase likelihood of participation. This will ensure the survey results are representative of the population of interest (i.e., all income levels, different levels of mobility, various lifestyle characteristics, and different cost-of-time values).

Survey costs are rising due to increased labor costs and the need to invest in new technologies, among other factors. It is usually the case that telephone surveys are significantly less costly to implement than are face-to-face interviews, and mail surveys are usually less costly than telephone surveys. Thus, interview costs for a second mode, regardless of which mode is used, are less than single mode surveys.

Survey organizations are responding to the needs of clients in the information age, who place a premium on reporting timely information for precisely defined market segments. Switching from one mode to another sometimes provides an opportunity for speeding the completion of a survey. For example, the number of interviewing stations limits the speed of telephone surveys. In large-scale surveys, greater speed can often be achieved by starting with mail questionnaires, all of which can be sent out at the same time, saving telephone and face-to-face contacts for nonrespondents.

Mixed Mode Surveys in Practice

Household Diary Study for the United States Postal Service (USPS). Prior to NuStats’ receipt of this multi-year research contract, USPS research was collected via face-to-face interviews. All final data on mail volumes and household demographic characteristics required large adjustments (sample weights) to mirror known mail volumes and household characteristics. NuStats is conducting the study using mixed mode combinations of telephone, mail and Web. The survey costs are greatly reduced compared to single-method surveys, data are more representative, and survey-reporting times have been substantially decreased.

Click here to go to the VOXCO web site. VOXCO hosts the Web portion of the USPS Household Diary Study.