Mixed methods research: combining quantitative and qualitative research

Multi-strategy research is becoming increasingly common in the social sciences, but this does not mean that it is seen as an inherently superior approach. Just like mono-method and mono-strategy research, multi-strategy research can only be successful if it is well designed and conducted by skilled researchers, and if the various research methods chosen are appropriate to the research questions.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 656-658

Another of the approaches to multi-strategy research is to combine the static view of events provided by quantitative research with the more processual picture provided by qualitative research. That is, qualitative research tends to focus on the everyday social processes of interaction that occur at a micro-level, which “fills in the gaps” left by quantitative depictions of macro-level patterns of events.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 645

Triangulation is one of many approaches to multi-strategy research, and it involves cross-checking the results of an investigation that used a method associated with one research strategy (e.g. a quantitative method) against the results from using a method associated with the other research strategy (e.g. a qualitative method).
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 638

It has been argued that quantitative research tends to reveal the larger scale, “macro” aspects of a phenomenon (such as patterns of crime or levels of educational attainment in different social groups), whereas qualitative research reveals the “micro” level processes of interaction that go on in everyday life. It is therefore extremely useful to combine these two levels of analysis and look at both aspects of a phenomenon, often through a two-stage research project.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 644,645

When a quantitative researcher is examining the relationship between two variables, they may find that this is obscured or moderated by an intervening variable. Qualitative research can help to identify such extraneous factors, or can be used simply to tell the researcher more about what the variables mean to the participants, which in turn helps them to understand the ambiguous findings.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 649

There is an argument for using a mixed-methods approach, apart from attempting to counter the arguments against. One of these is called the “technical” argument. In essence, this is the argument which distinguishes between data-gathering and (even) data-analysis techniques, as being autonomous, on the one hand and the espoused epistemologies of researchers on the other. This argument sees the ‘competing’ research strategies as compatible, making mixed methods research feasible.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 637

There are two main arguments against multi-strategy research. The embedded methods argument suggests that every research method is tied to a particular epistemological position that is incompatible with others. This argument has been answered in chapter 26 but is mentioned here again to force an understanding of the difference between a tool and its user. The other main argument against mixing quantitative and qualitative methods in a single study is called the paradigm argument. Paradigms are grand views of the world and of the methods available for scientific enquiry. Different paradigms are distinct from each other because of their divergent assumptions and methods. If quantitative and qualitative research indicates two separate paradigms, then they could never be mixed. Bryman asks whether that can be true (p636). It seems there are considerable areas of overlap and commonality between them.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 636

Qualitative research is sometimes used as the first stage of a project, with quantitative techniques forming the second stage. This allows researchers to explore their topic in an open-ended way, identify the most salient issues and then design a more focused, specific research instrument to address these, such as a questionnaire or a structured interview.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 638,639

Similarly, quantitative research can form an important first stage of a qualitative project, by informing the process of sample selection. For example, a survey questionnaire distributed to a large group of people might reveal various different social groups or types of respondent, some of which could be identified as potentially informative interviewees.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 638,639

Sometimes a researcher intends to conduct only a quantitative study but finds that the results they expected have failed to materialize, or to be as convincing as they might have hoped. In these circumstances, they might choose to use a second, qualitative method to find out why these results have emerged, and so end up conducting a multi-strategy research project after all. This might be more time consuming, but it saves the researcher from having to either reformulate their “quantitative” hypothesis and start again or abandon the research altogether.
Reference: Bryman: Social Research Methods: 5th Edition Page(s) 650,651