Big qual: the breadth-and-depth method of working with large amounts of qualitative data

NCRM news
Professor Rosalind Edwards and Dr Susie Weller, University of Southampton, and Dr Emma Davidson and Professor Lynn Jamieson, University of Edinburgh
A line of connected human figuresA line of connected human figures

How can you analyse large amounts of qualitative data in a way that retains the distinctive characteristics of rigorous qualitative research? This is a question increasingly faced by researchers working with qualitative data. They may have generated extensive quantities of interview material as part of a primary research project. Or they may be looking at sizeable sets of secondary qualitative data drawn from pooled sources deposited in data archives, or gathered from other resources such as social media.

The breadth-and-depth method of analysis was developed as part of the National Centre for Research Methods Phase III research programme in order to address the big qual question. The method supports qualitative researchers in a research data context where computational processing tools can manipulate enormous amounts of data speedily. The research context may also involve requirements for the archiving of qualitative data from primary research projects for sharing and reuse as part of open science debates, as well as drives to promote data sharing more broadly.

Working with big qual enables researchers to scope out research questions that allow for comparison, and for generalisability in the qualitative sense of how social processes work. The unique breadth-and-depth method can be used with any big qual material: primary or secondary, snapshot or longitudinal, and from single-sited, multiple-sited or separate multiple studies. It’s an iterative approach to managing and analysing large volumes of qualitative data that can be applied flexibly whatever the theoretical logic, substantive topic and nature of the qualitative data.

The analytic method consists of four main steps that allow researchers to combine extensive coverage with intensive illumination, moving between the span of big qual analysis and the detail of qualitative engagement. If you’re searching for existing relevant secondary data for your research, you start from Step 1. If you already have large amounts of qualitative data, you start at the next step.  

An archaeological metaphor

A good way of conveying this movement between breadth and depth is using an archaeological metaphor. Step 1 is a breadth element of the breadth-and-depth method. It’s like an archaeological ariel survey, used to gain a broad overview of the landscape of available potential secondary data. The purpose is to identify several sources of existing material that might be relevant to your research topic and questions.

Step 2 continues the breadth element, and archaeologically is like a geophysical survey. Geophysical surveying maps the patterning of landscape features and detects sub-surface areas of interest. This step uses computational text-mining approaches to identify areas of potential interest within the corpus and to point towards areas for preliminary deeper investigations.

Preliminary analysis is the third step and is where we begin to move from breadth to depth. Drawing on our archaeological metaphor, this step is like digging a shallow test pit into the data to see whether there’s anything of interest or not. We don’t go into the data in great depth. The fourth step moves us fully into the depth element, from examining extracts of data to the deep excavation of whole cases.  Deep excavation is part of the archaeological process of working with big qual that heralds the ability to bring depth back into conversation with breadth.

Learn to use the breadth-and-depth method

As part of the Timescapes 10 Festival, in collaboration with NCRM, we’re excited to be running a flexible online, self-directed course on how to work with the breadth-and-depth method. It amounts to around seven hours’ study over a three-day period. The course is tailored so that participants can dip in and out of resources and activities, self-directing their study to fit in with work and life commitments. We will be making pre-recorded videos, activity sheets, background reading and other resources available to participants through a dedicated online portal, and live online sessions are scheduled once a day with the course tutors for tailored support.

You can find articles explaining the breadth-and-depth method in the journal Quality & Quantity (2018) and (2021), and read an example of an application of the method in Sociological Research Online (2021). There is also a wide range of materials designed to help researchers think about, handle and analyse large volumes of complex qualitative data at our Big Qual Analysis Resource Hub.

Register for the Timescapes 10 Festival