As explained earlier, our research strategy is based on both survey data analysis as well as qualitative in-depth interviews. We thus employ a mixed-method design to investigate the phenomenon of cohabitation in Italy from different angles, using both quantitative and qualitative research methods.
However, this approach is far from nonproblematic: Since the beginning of the twentieth century, social and behavioral sciences have witnessed an ongoing “paradigm war” (Kelle 2001: 1) between proponents of the quantitative and qualitative paradigms. Whereas the latter profess “the superiority of ‘deep, rich’ observational data,” the former emphasize “the virtues of ‘hard, generalizable’ survey data” (Sieber 1973: 1335). The strengths of quantitative methods are seen in their ability to produce “factual, reliable outcome data that are usually generalizable to some larger populations,” whereas qualitative methods are strong in generating “rich, detailed, valid process data that usually leave the study participants’ perspectives intact” (Steckler et al. 1992: 2). For many decades, scholars held the view that the two paradigms are incompatible with each other (Howe 1988). It has been argued that the two approaches are based on different views of reality: the quantitative paradigm being that only one truth exists independently of human perception, and the qualitative paradigm assuming multiple realities are based on individuals’ constructions of reality (Sale et al. 2002).
Only recently, social and behavioral researchers have started to argue in favor of combining both approaches (e.g. Mayring 2001; Fielding and Schreier 2001; Jick 1979). Onwuegbuzie and Leech (2005), for instance, bring forward the argument that there are more similarities between both perspectives than there are differences. Researchers of both approaches incorporate safeguards in order to minimize bias; they attempt to triangulate their data, use
analytical techniques designed to maximize meaning from data, attempt to provide explanations of findings utilize techniques to verify data, and try to explain complex relationships that exist in the social science field. Mayring (2001) underlines that at the beginning of the twenty-first century, qualitative and quantitative approaches are no longer opposed to each other. The combination of both perspectives instead allows for using and relying on the strengths of the two paradigms. Mayring (2001) argues that both approaches may in fact profit from each other: Quantitative research might gain in openness toward the object of research and might take a step toward challenging concepts as well as hypotheses to a stronger extent. Qualitative research, in contrast, might obtain a higher level of transparency, which would allow for a stronger intersubjective traceability.
The extent to which both approaches complement one another becomes evident when considering the role of theory in qualitative and quantitative research. Whereas qualitative studies aim at theory building, quantitative research is targeted on theory testing and theory modification. Hence “neither tradition is independent of the other, nor can either school encompass the whole research process. Thus, both quantitative and qualitative research techniques are needed to gain a more complete understanding of phenomena” (Onwuegbuzie and Leech 2005: 380). Onwuegbuzie and Teddlie (2003) propose a re- conceptualization of both perspectives. Both authors suggest subdividing research into exploratory and confirmatory methods in order to unite qualitative and quantitative research under the same framework.
The advantages of mixed-method designs are recurrently emphasized in recent literature. Two basic arguments prevail: The first argument refers to the achievement of cross-validation or triangulation, that is mixed-method studies are assumed to complete our understanding of a phenomenon. The second argument regards the achievement of complementary results by using the strengths of one approach to enhance the other (Sale et al. 2002). A third – and less emphasized – argument is found in the fact that the combination of qualitative and quantitative methods allows for investigating a phenomenon from two perspectives, namely from the micro and the macro perspectives (Onwuegbuzie and Leech 2005).
Steckler et al. (1992) refer to four different ways that permit the integration of qualitative and quantitative research methods into one common research design: (1) Qualitative methods are used to help develop quantitative measures and instruments; (2) qualitative
methods are used to help explain quantitative findings; (3) quantitative methods are used to embellish a primarily qualitative study; and (4) qualitative and quantitative methods are used equally and in parallel.
Independent of the concrete research design, Greene et al. (1989, cited in Onwuegbuzie and Leech 2005) emphasize five broad purposes of mixed methodological studies: triangulation (seeking convergence of results from different methods), complementarity (seeking clarification of results coming from one method with the findings from the other method), development (using the findings from one method to help inform the other method), initiation (discovering contradictions that lead to a re-framing of the research question), and expansion (seeking to expand the breadth and range of inquiry).
In sociological and demographic studies, the importance of mixed methodological research approaches is in fact rising. Bernardi and Hutter (2007), for instance, point to the increasing role of anthropological theory and methods in the field of demography, paying particular attention to family and fertility research. An example of this kind of study is the work of Bledsoe et al. (2007). The authors combined municipal register data with exploratory fieldwork to study high-fertility Gambians in low-fertility Spain. Another example is the research by Rossier (2007). On the basis of ethnographic literature and qualitative studies, she used representative surveys to investigate attitudes toward abortion and contraception in Burkina Faso.
In our study, we aim to take advantage of the combination of both methodological paradigms. We believe in the capacity of integrating qualitative and quantitative research methods for gaining deeper insights into the phenomenon of cohabitation development in Italy. Accordingly, we employ two different methods to investigate one phenomenon. In doing so, we make use of both methods equally. However, as the two approaches refer to different kinds of research questions (as described above, the qualitative approach aiming at exploring data, and the quantitative approach targeting the confirmation of theories), we use each approach to investigate a different problem: Whereas survey data analysis aims at measuring the effect of several individual and background characteristics on informal union formation, in-depth interviews form the basis for analyzing the underlying motivations, perceptions, and attitudes that are relevant to entering cohabitation. In our study, we use each method separately, which means that the separate quantitative and qualitative analysis will
be followed by a combination of findings combing from both investigations. We hope that the findings from one approach will help us understand the results from the other approach. This way, we expect to gain a deeper understanding of cohabitation diffusion in Italy than one method alone would permit.