In October 2009 Interrogare GmbH executed a mobile survey as a method test in cooperation with PAYBACK, during which preferences for a planned iPhone app were measured with the aid of the MaxDiff method. Due to a response rate of 85% it was possible to complete 201 interviews with iPhone users within a couple of days.

For the study executed by Interrogare iPhone users were recruited from the PAYBACK panel and invited to the questionnaire via personalized text messages. The survey focused on measuring the participants' preferences with regard to different functionalities that an iPhone app by PAYBACK might offer. For the measurement the MaxDiff method was employed, which offers the possibility to determine a complete ranking of all functionalities by means of a simple sampling technique.

In order to make participation in the survey as comfortable as possible, the questionnaire was optimized for display on the iPhone. The main focus was on full support of all survey functionalities. The willingness to participate among the target subjects proves the high degree of acceptance for mobile surveys.

Daniel Rieber, Head of Onsite & Tracking Services at Interrogare, reports: "After the first few hours of field time we had already achieved a response rate of 80%; at the end of the two days' field time it amounted to 85% with 201 completed questionnaires."

PAYBACK GmbH was very satisfied with the results that proved extremely helpful for the development process of the iPhone app. Dietmar Zentner, Head of Market Research at PAYBACK, said: "We love to cooperate with the motivated Interrogare team, particularly when it comes to innovative methods. The use of a mobile survey with an exactly defined, relevant group of people with the specific device makes sure that we obtain concrete and viable results."

The method developed by Interrogare is especially being tested for and made available to market research institutes and consultancy businesses.