Survey Methodology

In its research, infas uses the entire spectrum of scientifically recognized survey methods: from telephone, face-to-face and online surveys to written-postal surveys and qualitative research methods. In doing so, we use our own resources and thus ensure consistent quality control.

When collecting data, the infas social research institute always uses state-of-the-art technology and methods. infas is certified according to the international standard ISO 20252 for market, opinion and social research by Austrian Standards.

The data collection processes at infas are subject to uniform standards, which are controlled centrally via a dedicated sample management system. infas thus ensures up-to-the-minute information with maximum transparency on the status of field work for each study.

Progress on data collection is reported on an ongoing basis based on documentation of contact attempts during the entire field period. In-depth analyses with all parties involved in the project lead to individually coordinated contact strategies and measures in the course of the field.

Our primary goal is, on the one hand, the careful processing of a sample according to methodological standards – with high exhaustion with the lowest possible bias and the highest data quality. On the other hand, all necessary measures to minimize interviewer effects are observed during interviewer deployment.

Face-to-face interviews (CAPI) remain the main mode of empirical research. Especially in combination with the numerous other survey modes, this traditional variant offers new possibilities and perspectives.

With its own nationwide staff of interviewers, infas conducts extensive ad hoc surveys and sophisticated panel surveys with a wide variety of target groups. The interviewers are specially trained to conduct social science interviews and are also up to challenging surveys (household surveys, difficult target groups, handling complex survey instruments, B-to-B context).

The key competencies of infas for face-to-face interviews include:

  • Highly qualified interviewers who are continuously trained and further qualified on the basis of key performance indicators;
  • Monitoring and control of the interviewers by our own quality management team (QS);
  • Interviews with laptop, tablet or handheld as Computer Assisted Personal Interviews (CAPI), Computer Assisted Self Interview (CASI) or classic as paper-pencil interviews;
  • complete documentation and tracking of contacts via electronic contact logs;
  • Flexible implementation of operational and field strategy measures based on indicators from contact logs and survey data – also at interviewer level;
  • Any combination with other survey modes;
  • Use of complex survey instruments, including (computer-based) competency tests, video recordings, or physical measurement instruments.

Telephone surveys (CATI) have been part of the spectrum of relevant survey modes at infas for many years. Through the cooperation with the sister company CATI-LAB GmbH, capacities are available for this at two locations in Bonn and Nuremberg. Additional capacities in Luxembourg are used in particular for foreign-language surveys.

Interviews by telephone at infas are optimally optimized for the special challenges: With the dual-frame approach, for example, infas is countering the displacement of the classic fixed-network connection by mobile communications. The infas social research institute has made a significant contribution to the development of this approach, so that mobile phone numbers are now included in the sample frame for all population samples. For studies conducted by telephone, infas also uses numerous verified procedures to ensure quality and exclude possible sampling bias.

The main competencies of infas for telephone surveys include:

  • Highly qualified interviewer staff, especially for social science interviews, who are continuously trained and further qualified on the basis of key performance indicators;
  • Interviewers with foreign language skills for study assignments at home and abroad;
  • Client involvement in all steps of the telephone survey, including participation in study-specific interviewer training, pretesting, and monitoring interviews in real time;
  • Flexible contact control and customized resubmission algorithms to optimize study exhaustion;
  • Complete documentation and tracking of contacts throughout the fieldwork.
  • Flexible implementation of field strategy measures based on key figures from contact logs and survey data;
  • Any combination with other survey modes.

infas applies the same high and proven quality standards to online surveys as to offline surveys. In the fast-moving digital sector, new instruments and techniques are constantly being tested and used if they are suitable.

infas pays special attention to the careful elaboration of the web-based survey instruments. This is important because, unlike other survey modes, respondents complete an online survey alone and without assistance. Wherever possible, infas works with precisely defined populations and addressable target groups in order to ensure requirements such as representativeness, random selection and selection-free access. In the case of a survey based on online access panels, infas works exclusively with providers who meet the requirements of the ADM. If required, infas offers the recruitment of target persons offline.

At the infas social research institute, online surveys are often used as a multi-mode survey, i.e. in a mix of modes. The target group is thus given the opportunity to participate in a survey on different modes – an important option for increasing response rates.

infas’ competencies for online surveys include:

  • Implementation of the online questionnaire with all online-specific design options,
  • Responsive design for use on mobile devices as well,
  • Hosting of the online surveys on infas’ own servers,
  • digital access to a wide range of target groups (also via telephone, face-to-face or mail-screening),
  • any combination of online surveys with other survey modes,
  • in cooperation with the company’s sister infas 360 optional small-scale regional localization of online respondents.

Even in the age of the Internet and online research, mail surveys are indispensable. They are firmly established in the social sciences as an adequate method of data collection and have not been displaced by online surveys. Mail surveys can reach people who do not have Internet access or for whom no telephone number is available. They are the method of choice to reduce interviewer effects..

In combination with online surveys, they provide the first access to addressable target groups and may appeal to older target groups who are less likely to be motivated to participate by online surveys. Feasible in multi-mode studies are combinations with face-to-face interviews by allowing interviewers to persuade respondents by offering an alternative response option. The main competencies of infas for Mail surveys include:

  • Professional implementation and design of paper based survey instruments (such as questionnaire, cover letter, privacy statement, etc.) including print production,
  • comprehensive organization and control of questionnaire mailings and response collection,
  • Case-by-case documentation and follow-up throughout the survey process,
  • Flexible implementation of field strategy measures based on analyses from mailings and Office returns,
  • Combination with other survey modes, especially online surveys.

Qualitative surveys are often used during the operationalization and preparation phases of studies. They support idea generation or form a supplement to quantitative surveys. As a stand-alone procedure, they can also be used on a larger scale, especially in evaluation studies.

For group discussions or focus groups, infas has experienced, psychologically trained moderators who have several years of experience in various subject areas. infas uses selected studios in all regions nationwide that meet the requirements in a social science context. In the case of explorative, guideline-based interviews, expert interviews as well as in-depth interviews, infas successfully conducts interviews with difficult or demanding target persons or semi-structured interviews. The institute has employees who can meet all participants in the discussion (e.g. top management level) at eye level.

infas regularly applies the following qualitative survey methods:

  • Group discussions or focus groups ,
  • social science expert interviews,
  • Online group discussions and online chats,
  • Cognitive test interviews,
  • social science content analysis and desk research,
  • Observation and experiment.

Multi-mode surveys

infas knows how to combine online, telephone, face-to-face or mail interviews as needed. We survey regardless of which survey mode respondents prefer.

A study participant does not want to answer on the phone, but online in a timely manner? No problem, we send the questionnaire link or vice versa? No issue, we call directly? Or would you rather send it by letter? This is also possible. infas combines survey modes as desired.

As a result, we achieve a higher willingness to participate and higher response rates. This is because the flexibility of being able to offer different survey modes in simultaneously. Furthermore, with a sequential use of different survey modes, more difficult target groups can be addressed, and alternative survey options can be offered in different stages. Acceptance and willingness to participate increases at the individual levels by reaching different target groups. The multi-mode approach ends up minimizing survey bias and selectivity effects.

However, using different quantitative survey modes in a study is challenging and has consequences for sampling, handling during the field phase, data preparation, weighting, and analysis. For this reason, the institute has tools developed in-house as well as firmly established procedures that have been tested countless times to enable the simultaneous combination of different survey modes in a scientifically sound manner.

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Quality assurance (training and interviewer control)

The quality assurance routines and procedures are an integral part of the surveys at infas. They are already initiated by the sequential training programs.

A qualitatively adequate general training of interviewers is obligatory at infas. The comprehensive general training program teaches the correct use of questionnaires and interview techniques, the standardized interviewing, but also how to approach and motivate target persons and how to deal with critical contact and interview situations.

The subsequent study-specific training subsequently prepares the interviewers for actual use in the respective study. One- to multi-day events are held by the project management and – if desired – with customer participation to prepare the interviewers for the methodological requirements of the study and the handling of the survey instruments.

Training concepts at infas range from simple lectures and presentations, to interactive concepts with role plays, exercises in small groups or side-by-side coaching sessions, to modular programs with self-study learning units or knowledge tests.

It is undisputed that well-educated and trained interviewers contribute significantly to the quality of the data collected and the success of a survey.

In addition to the training programs, field monitoring processes and interviewer controls form another central component of quality assurance at infas. Current field information and interview data are available to observe metrics of both sample processing and adherence to methodological standards in data collection. Possible interviewer effects will also be investigated by the Statistics Department using intracluster correlation analyses.

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