Survey data is the central tool of empirical social research. At the same time, however, there is also a long tradition of combining this data with other forms of data collection: whether register data, document analyses, microgeographical data or interview observations. In recent years, biologically relevant data has therefore become increasingly important.
On the one hand, these are used to determine health characteristics (e.g. hand grip strength, lung function measurements, SARS-CoV-2 antibody determinations, etc.). On the other hand, sociology is also increasingly recognizing that genetics and the social environment cannot be considered independently of each other and that the social sciences should make a greater contribution to the study of this interaction. Interest in genetic information is therefore also growing in the context of social science surveys. Against this background, the relatively new field of epigenetics, which deals with the influence of the (social) environment on the activity of certain genes, also appears to be particularly exciting.
For many years, infas has been conducting studies in which various forms of biological data are collected. Taking into account the special research ethics and data protection requirements and implementation conditions, this type of data can offer important added value for many studies. If a study design is to combine surveys with the collection of biological or genetic data, special requirements must be observed. For example, the approval of an ethics committee must be obtained regularly before conducting such studies.
“Without taking genetic disposition into account, the causal influence of the social on the social cannot be determined without distortion.”
(Schupp/Wagner 2010, 3)
It should also be checked whether the biological data can be collected by the interviewee themselves or an appropriately trained interviewer, or whether medically trained personnel are required for this. Examples of the former include giving saliva samples, taking capillary blood from the fingertip or carrying out measurements of hand grip strength or lung volume. All types of invasive procedures, such as venous blood sampling, require appropriately trained personnel. Both interviewers and medical staff must receive project-specific training before the procedure is carried out. This also applies if the survey is carried out by the interviewee themselves, but in the presence of an interviewer, so that the survey can be carried out as standardized as possible and questions from the interviewees can be answered appropriately. And even if medical staff are used, it should be borne in mind that conducting surveys or home visits is very different from the situation in doctors’ surgeries or clinics.
Of course, participation in surveys and thus also the collection of biological data is voluntary and requires the consent of the participants. It should be noted that informed consent requires not only information about the nature of the data, the purposes of the analysis and the forms of storage and revocation options, but also an understanding of this information. Particularly when collecting genetic data (usually by means of self-administered saliva samples), explanations can quickly turn into an introductory course in genetics.
In addition to data protection requirements, it is also important to bear in mind that the methodological demands on the informative value of surveys also apply to biological data and therefore not only the highest possible willingness to participate, but also one that is free of selection. Depending on the type of biological data to be collected, there are considerable differences in the complexity of the implementation. If you remember the different rapid tests in the corona pandemic, it becomes clear that even for a relatively simple test procedure, clear instructions are essential. In addition to illustrated instructions, instruction videos have proven to be particularly helpful. It is important that the instructions cover all steps and materials, from unpacking to shipping.
In many studies, the biological data is collected as part of interviewer-administered surveys by or at least under the guidance of interviewers. This is because even if the survey is carried out by the interviewer, the appropriately trained interviewers can provide support in explaining the procedure and the materials and – not least due to the opportunity to ask questions directly in the situation – usually also increase the willingness to participate. However, there are also studies in which the material is sent by post and the survey is purely self-administered. Here, too, it has been shown that an accompanying telephone reminder, in the context of which questions about the implementation can also be clarified, can have a positive effect on the willingness to participate.
While measurements of hand grip strength or lung function are directly documented by interviewers within the household interview situation and thus become part of the survey data, many types of biological samples must first be analyzed. This requires cooperation with medical laboratories. How much time can pass between the sample being taken and analyzed and what special shipping or storage conditions apply depends on the type of sample. While a saliva sample can be preserved for a longer period of time with the help of stabilizers in the test tube, venous blood samples are subject to more complex storage and delivery requirements.
Even if special requirements need to be taken into account during implementation, experience in large population studies has shown that the combination of surveys and biological data can be implemented in practice. For many research questions, this enables a meaningful expansion of the analysis options and, not least, encourages multidisciplinary collaboration, e.g. with geneticists, health researchers or psychologists.
About the studies:
In the TwinLife twin family study, survey data is supplemented by various types of biological data. For example, self-administered saliva samples were taken several times and the interaction between genetics and (social) environment on the development of social inequality was investigated using the genetic data collected. Further information can be found on the study website: https://www.twin-life.de.
The study “Corona Monitoring – Wave 2” (RKI-SOEP-2) conducted in 2021/2022 investigated how many people were already infected with the SARS-CoV-2 coronavirus without realizing it, how many people have already been vaccinated and how long antibodies have been detectable in the blood. For this purpose, self-administered dry blood samples were also taken by the interviewees, which were then used to determine the antibodies against SARS-CoV-2 (see Bartig et al. 2022).
Read more:
Bartig, S., Brücker, H., Butschalowsky, H., et al. (2023): Corona Monitoring Nationwide (RKI-SOEP-2): Seroepidemiological Study on the Spread of SARS-CoV-2 Across Germany. Jahrbücher für Nationalökonomie und Statistik, Vol. 243 (Issue 3-4), pp. 431-449.
Conley, Dalton (2009): The Promise and Challenges of Incorporating Genetic Data into Longitudinal Social Science Surveys and Research, in: Biodemography And Social Biology, Vol. 55, No. 2, pp. 238-251.
Council, National Research (2001): Cells and Surveys, National Academies Press eBooks.
Diewald, M., Kuznetsov, D., Liu, Y. (2024): Unequal life chances through the epigenome? On the interaction of biological and social mechanisms, in: Springer eBooks, pp. 1-24.
Heil, R., Seitz, S., Robienski, J., König, H. (2015): Introduction, in: Springer eBooks, pp. 7-14.
Schupp, J., Wagner, G. (2010): On the “why” and “how” of collecting (genetic) “biomarkers” in social science surveys, in: SOEPpapers On Multidisciplinary Panel Data Research.
This article was first published in Lagemaß 14 “wählen”.