Where economics is dominated by a monolithic methodology of axiomatic theorizing and econometric analysis of secondary data sets, multiple and mixed methods research offers a much richer toolkit to examine economic problems from a variety of perspectives with custom methods suited for the particular task. Rather than limiting analysis to the application of approved methods to an approved data set, with little consideration of its content, a multiple or mixed methods approach inherently interrogates choices and limitations of data and methods from the outset. Multiple and mixed methods research is of particular value to heterodox economics because heterodox concerns are broader than those of orthodox economics; explaining and advocating change in the social provisioning process in general including institutions, power and ideology. As argued in Part I of this Handbook, the critical realist ontological foundations of heterodox enquiry demand a research strategy consistent with this, one that embraces contestation, plurality, emergence and interdisciplinarity. Thus heterodox economics inherently rejects any preference for particular method or data and must be open to multiple and mixed methods.

But openness to multiple and mixed methods is insufficient in itself to advance a heterodox research agenda. A learned understanding of multiple and mixed methods design is needed to select appropriate tools to investigate particular problems, to use them well and appropriately combined with other tools, and to clearly understand the limitations of orthodox approaches. This chapter aims to equip readers with a grounding in the principles of multiple and mixed methods research and to consider benefits and limitations of triangulation of methods, issues in research design, choices of methods and their integration, and issues of validity and ethics.