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Home > Education & Research > ISTSS Research Guidelines > Trauma Research Methods > An Introduction to Qualitative Research Methods for Studying Trauma

An Introduction to Qualitative Research Methods for Studying Trauma


ISTSS eNewsletter, Traumatic StressPoints, June 2007


Carl F. Auerbach, PhD
Yeshiva University

This introductory article on qualitative research methods for trauma research is sponsored by the ISTSS Research Methods Special Interest Group and the Conference on Innovations in Trauma Research Methods (CITRM).  It is based on a presentation by Carl Auerbach at the 2006 CITRM meeting.

As a casual perusal of the Journal of Traumatic Stress shows, the vast majority of trauma studies are conducted using traditional, standard quantitative research methodology. The goal of this article is to examine an alternative methodology for studying trauma — qualitative research. Before beginning, it is necessary to narrow the article’s scope, because a comprehensive account of qualitative trauma research is not possible in a short space, any more than a comprehensive account of quantitative trauma research would be. In order to narrow the topic down to manageable size, this article will focus on the grounded theory approach to qualitative research (Strauss & Corbin, 1998), and within that tradition, the version of grounded theory that my colleague Louise Silverstein and I have developed (Auerbach & Silverstein, 2003).

The article itself is organized into sections, each examining a “frequently asked question” about qualitative research, including:  

  1. What is qualitative research?
  2. Why would you do qualitative research?
  3. How do you design a qualitative research study?
  4. How do you analyze qualitative data?
  5. Where can you learn more about qualitative research?

What is Qualitative Research?
Qualitative research refers to a broad family of research methodologies, each of which differs from traditional quantitative research, that may be described as follows:

Qualitative research is research that involves analyzing and interpreting text and interviews and observations in order to discover meaningful patterns descriptive of a particular phenomenon.

The definition contrasts qualitative and quantitative research in two ways. First quantitative research involves numbers whereas qualitative research involves patterns, or stories. Second, analyzing quantitative data involves computation, whereas analyzing qualitative data involves interpretation. To illustrate, a research study of the personality variables that predict PTSD in people diagnosed with cancer would be quantitative research, whereas a study of their experience as cancer patients would be qualitative research.

Note that the terms overlap somewhat, so that content analysis might reasonably be considered qualitative research, quantitative research, or a blend of both.

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Why Would You Do Qualitative Research?
There are several possible answers to this question:

  • When you don’t know enough to do hypothesis testing research and so want to do hypothesis-generating research. Traditional hypothesis testing research involves choosing independent and dependent variable(s), and predicting a relationship between them. If you do not feel in a position to formulate hypotheses in this form, but nevertheless want to understand a phenomenon, then qualitative research may be the method of choice.    
  • When you want to study phenomena in a culture about which there is limited information. The need for hypothesis generating research is particularly strong when one is investigating cultural and diversity research, precisely because we are rarely in a position to state meaningful hypotheses for cultures different from our own. For example, a student dissertation investigated traumatization in Cambodian refugees who fled the Khmer Rouge and came to live in the South Bronx (Shiro-Gelrud, 2001). At the time that the study was planned there was not enough information to formulate meaningful hypotheses about this particular community, a situation which is at least partly true even now.
  • When you are interested in people’s subjective experience for clinical and/or policy reasons. For example, a qualitative study of cancer patients would be useful to clinicians who want to work with this population, and for policy makers who want to develop programs to work with them.

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How Do You Design a Qualitative Research Study?
The process of designing a qualitative research study can be organized into five steps, each of which parallels a step in designing a quantitative research study. Each of these steps requires the qualitative researcher to do something that quantitative research would regard as “unscientific,” imprecise, and insufficiently rigorous. The end result, as shown in Table 1, is a different kind of study. The first two columns of Table 1 contrast how quantitative and qualitative methodology handle each design step. The third column, headed “permission,” describes what qualitative research allows but which quantitative research prohibits. This will be illustrated in terms of the "South Bronx Cambodian Refugee Study" (Shiro-Gelrud, 2001).

  • Literature Review. Designing qualitative and quantitative research both begin with a literature review. In the quantitative paradigm the function of the literature review is to find out what is already known and develop this knowledge further. In the qualitative paradigm the function of the literature review is to find out what is not known. Hence the qualitative paradigm gives you permission to not know. For example, very little was known about the population of Cambodian refugees.
  • Formulation. In the quantitative paradigm the research hypothesis must specify how an independent variable (or variables) affects a dependent variable (or variables). In contrast, the research focus of a qualitative study need not be so definite. Qualitative research permits, indeed encourages, a broad research focus.  For example, it can be as broad as understanding the experience of Cambodian refugees.    
  • Instrumentation. Quantitative research requires that the researcher make use of psychometrically validated measurement scales. Qualitative research, in contrast, assumes that the researcher does not know enough to develop such instruments. Rather, the research participants are assumed to be experts on their own experience, capable of teaching the researcher what she or he needs to know. The research participants are enlisted as co-investigators, and the research interview becomes a collaborative conversation in which both parties investigate the research participant’s experience. Thus, the permission to not know is accompanied by a permission to ask. For example, the experience of Cambodian refugees was investigated simply by asking them about it.
  • Sample Selection. In quantitative research a random sample of the population of interest is used in order to allow for generalization. In qualitative research, generalizabity is not an issue. Rather, the sample is selected in order to develop theory, and questions about the developed theory are answered by additional sampling. Thus, qualitative research gives permission to explore. For example, the initial study of Cambodian refugees used only successful, resilient community leaders. Having learned how they coped, subsequent studies could explore the experience of less resilient individuals.
  • Sample Size. In quantitative research the sample size is selected using a power analysis procedure that takes into account effect size and also desirable type 1 and type 2 errors. In qualitative research the sample size is not determined in advance. Rather, theory is generated as the sampling proceeds, and sampling ends when theoretical saturation occurs; that is, the researcher has interviewed enough participants that no new information emerges from their stories. Thus, qualitative research gives permission to theorize during data collection. For example, theoretical saturation occurred for the Cambodian refugees after six participants were interviewed.     

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How Do You Analyze Qualitative Data?
The aim of qualitative research is to analyze data in order to generate theory. Because the theory is generated from the data itself, the theory thus generated is referred to as grounded theory, because the theory is grounded in the data (Strauss & Corbin, 1998). The process of generating theory from data is called coding. My colleague Louise Silverstein and I have developed a step-by-step procedure for generating grounded theory from data (Auerbach & Silverstein, 2003). Its application to research on trauma is presented here, and illustrated in terms of Cambodian refugees.

Our method uses a three-level coding approach that begins with bottom-up coding, i.e. starting with the text itself, and proceeds to a top-down approach which links data from a particular study to broader psychological theory. We begin the bottom-up phase by reading the transcripts of sessions carefully, and identifying segments of Relevant Text, i.e. words and phrases that are relevant to our research focus. In this case, Relevant Text would be any text that refers to traumatic experience.

In the first level of coding, we group Relevant Text, i.e. segments of text that express more or less the same idea, into Repeating Ideas. After identifying the Repeating Ideas, these are grouped into a second, more abstract level called Themes. Themes represent more general ideas implicit in the Repeating Ideas. Each level of organization subsumes the level below it.  That is, each Repeating Idea is a cluster of segments of Relevant Text, and each Theme is a cluster of Repeating Ideas.

After the Themes are identified, the top-down phase begins. We link our Themes to Theoretical Constructs found in our original theoretical framework (because we are exploring trauma, our Theoretical Constructs in this example are all derived from trauma theory). The Theoretical Constructs are then organized further into a Theoretical Narrative that tells the story of the subjective experiences of the participant(s). This story, organized around the Theoretical Constructs, generates hypotheses (i.e. a hypothetical answer(s) clarification of our research focus). To provide an example of our coding technique, we present a brief excerpt from a Theoretical Narrative describing the experience of Cambodian refugees. In what follows the Theoretical Constructs are presented in capital letters, the Themes in italics, and the repeating ideas in quotes.

At the end of April 17, 1975 everything changed overnight. The Khmer Rouge came and the killing fields started. (SHATTERING OF THE ASSUMPTIVE WORLD). “You worked hard during the Khmer Rouge but you got starvation. You were scared that some day they were going to take you away to kill you.” (vulnerability). Your family stated in the countryside while you were working in the capital. “The government controlled everything. They cut communication. People got killed because they talked too much. During the war you didn’t talk.” (isolation)

For more details of the Theoretical Narrative, see Shiro-Gelrud (2001).

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Where Can You Learn More About Qualitative Research?
Starting points for going further are given in the references. Strauss and Corbin (1998) is the classic text and should be read. Flick’s (1998) book gives a good overview of the qualitative research process. Hill, Thompson, and Williams (1997) describe consensual qualitative research, an alternative to our method. The Handbook of Qualitative Research (Denzin & Lincoln, 2000), contains chapters on every aspect of qualitative research, and these should serve as a guide to a rapidly developing literature.
Auerbach, C. F., & Silverstein, L.B. (2003). Qualitative data: An introduction to coding and analysis. NY: NYU Press.
Denzin, N. K., & Lincoln, Y. S. (Eds.). (2000). Handbook of qualitative research (2nd ed.). Thousand Oaks, CA: Sage.
Flick, U. (1998). An introduction to qualitative research. Thousand Oaks, CA: Sage.
Hill, C. E., Thompson, B. J., & Williams, E. N. (1997). A guide to conducting consensual qualitative research. The counseling psychologist, 25, 517 - 557
Shiro-Gelrud, E. (2001). Resiliency and post-traumatic growth: Transforming power of trauma in Cambodian refugees. Unpublished Doctoral Dissertation, Yeshiva University.
Strauss, A. & Corbin, J. (1998). Basics of qualitative research: Techniques and procedures for developing grounded theory. Thousand Oaks, CA: Sage.

Author Note
Carl F. Auerbach, Ferkauf Graduate School of Professional Psychology, Yeshiva University.
Correspondence concerning this article should be addressed to Carl Auerbach, Ferkauf Graduate School of Professional Psychology, 1300 Morris Park Avenue, Bronx, NY, 10461. 

Table 1
Comparison between quantitative and qualitative research


Research Design Step Quantitative Hypothesis
Qualitative Hypothesis
Literature Review Research problem developed to confirm, extend, or refute existing theory Research problem developed from gaps in existing theory to generate new theory Permission to not know
Formulation Research hypothesis to be tested Research focus to be investigated Permission to be broad
Instrumentation Operationalize independent and dependent variables Narrative interview (collaborative conversation) Permission to ask
Sample Selection Random sample to allow generalization Theoretical sample to facilitate theory development Permission to explore
Sample Size Power analysis determines sample size Theoretical saturation determines when sampling ends Permission to theorize during data collection