Combine qualitative and quantitative data

Using a combination of qualitative and quantitative data can improve an evaluation by ensuring that the limitations of one type of data are balanced by the strengths of another. This will ensure that understanding is improved by integrating different ways of knowing. Most evaluations will collect both quantitative data (numbers) and qualitative data (text, images), however it is important to plan in advance how these will be combined.

Options

When data are gathered

Parallel Data Gathering: gathering qualitative and quantitative data at the same time.
Sequential Data Gathering (Sequencing): gathering one type of data first and then using this to inform the collection of the other type of data.

When data are combined

Component design: collecting data independently and then combining at the end for interpretation and conclusions.
Integrated design: combining different options during the conduct of the evaluation to provide more insightful understandings.

Purpose of combining data:

Enriching: using qualitative work to identify issues or obtain information on variables not obtained by quantitative surveys.
Examining: generating hypotheses from qualitative work to be tested through the quantitative approach.
Explaining: using qualitative data to understand unanticipated results from quantitative data.
Triangulation (Confirming/reinforcing; Rejecting): verifying or rejecting results from quantitative data using qualitative data (or vice versa)

Resources

Guides

Introduction To Mixed Methods In Impact Evaluation: This guide, written by Michael Bamberger for InterAction outlines the main elements of a mixed methods approach with particular reference to how MM can be used in an impact evaluation.
Conducting Mixed-Method Evaluations: This technical note from the US Agency for International Development (USAID) provides an overview to using a mixed-methods approach for evaluation and outlines some of the important considerations that must be taken into account when using the MM approach.
Conducting mixed methods research: These YouTube videos feature Alan Bryman from the University of Leicester School of Management presenting a lecture focused on the use of a mixed methods approach when conducting research.

Sources

Caracelli, Valerie J. and Greene, Jennifer C. (1997). "Crafting mixed-option evaluation design." In J. C. Greene and V. J. Caracelli (eds.), Advances in mixed-option evaluation: The challenges and benefits of integrating diverse paradigms. New Directions for Program Evaluation, No. 74. San Francisco, CA: Jossey-Bass, pp. 19-32.460

Carvalho, S. and H. White. (1997) ‘Combining the quantitative and qualitative approaches to poverty measurement and analysis’, Technical Paper 366. The World Bank: Washington D.C.466

Greene, J. (2007) Mixed Options in Social Inquiry. San Francisco: Jossey-Bass.465

Greene, Jennifer C., Caracelli, Valerie J. and Graham, Wendy F. (1989). "Toward a conceptual framework for mixed-option evaluation design." Educational Evaluation and Policy Analysis, 11(3), pp. 255-74.459