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48 PART 1: An Overview of the Approach to and Organization of Critical Care

disease is more common. Returning to our previous example, but assum- analyzing the same data, member checking, with draft findings reviewed
ing that the test in question has a sensitivity and specificity of 95% by participants for accuracy, or theory triangulation, in which findings
are correlated to existing social theory.
# A Patients With Disease
Given That Positive Predictive Value = As with quantitative studies, questions may arise about the generaliz-
Total # of Patients Testing ability of qualitative findings. It is important, however, to recall that the
Positive purpose and structure of qualitative methods are such that generaliz-
If the disease prevalence is 1%, PPV = 19/59 = 0.32 or 32% ability is often not the intended goal. The goal of qualitative methods is
more often to understand the range of behaviors and concepts within a
But if the disease prevalence is 10%, PPV = 190/280 = 0.67 or 67% specific context. Thus, although qualitative methods may generate many
hypotheses and theories, much of what is learned using these methods
■ QUALITATIVE DATA AND ITS ROLE IN CRITICAL CARE RESEARCH must be further assessed on a population level to understand whether
https://kat.cr/user/tahir99/
the findings may be appropriately applied in broader contexts.
The vast majority of critical care research is quantitative in nature.
That is, it tests well-articulated hypotheses and assesses outcomes that SUMMARY
may be counted or measured on either an objective or subjective scale.
Qualitative research, on the other hand, tends to answer the “what,” A rational approach to the clinical interpretation and application of
“how,” and “why” questions rather than the questions of “how many” research findings at the bedside can lead to effective translation of sta-
or “how much.” Qualitative methods can serve a variety of purposes tistically significant findings to clinically meaningful interventions. It is
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in critical care research. They can be used for initial hypothesis gen- incumbent on all clinicians to develop a system for critical appraisal of
eration or theory development. Another valuable role for qualitative the literature that is both well reasoned and efficient. Both our intellec-
research is the investigation of anomalous findings from quantitative tual integrity and our patients’ best interests depend on it.
studies. Qualitative methods include data collected from a broad range
of sources including direct observation and ethnographic studies
24
semistructured interviews or focus groups, 25,26 document analysis, and
mixed methods. 27,28 Qualitative methods have demonstrated usefulness KEY REFERENCES
in areas of investigation including, among others, end-of-life care, 29-32
transitions of care and follow-up, 25,26 and team dynamics. 33 • Dans AL, Dans LF, Guyatt GH, Richardson S. Users’ guides to the
Giacomini and colleagues have outlined helpful guidance on the medical literature: XIV. How to decide on the applicability of clini-
interpretation of qualitative research in health care, advocating a system- cal trial results to your patient. Evidence-Based Medicine Working
atic approach that addresses key aspects of assessing study validity. 34,35 Group. JAMA. 1998;279(7):545-549.
Such an assessment requires evaluation of (1) participant selection, • Giacomini MK, Cook DJ. Users’ guides to the medical literature:
(2) choice of data collection method, (3) comprehensiveness of data XXIII. Qualitative research in health care A. Are the results of the
collection, and (4) rigor of data analysis and corroboration of findings. 34 study valid? Evidence-Based Medicine Working Group. JAMA.
A high-quality study will have a clearly defined research question 2000;284(3):357-362.
and will explicitly state how the participants recruited to the study were • Giacomini MK, Cook DJ. Users’ guides to the medical literature:
chosen to answer the stated question. Such a study will also outline in XXIII. Qualitative research in health care B. What are the results
its methods specifically why a particular data collection method was and how do they help me care for my patients? Evidence-Based
chosen: Was direct observation chosen as the study method? If so, was Medicine Working Group. JAMA. 2000;284(4):478-482.
the presence of the observer likely to have influenced the behavior of the • Green J, Thorogood N. Qualitative Methods for Health Research.
participants? Were there multiple methods used in the same study and, London: Sage Publications; 2004.
if so, what did each method contribute? Why was one method chosen
over another? What evidence is there that the chosen method was the • Guyatt GH, Sackett DL, Cook DJ. Users’ guides to the medical
appropriate one to gain the desired information? literature. II. How to use an article about therapy or prevention.
Credible qualitative methods should demonstrate comprehensiveness A. Are the results of the study valid? Evidence-Based Medicine
in both data collection and analysis. Unlike studies on the quantitative Working Group. JAMA. 1993;270(21):2598-2601.
end of the research spectrum, qualitative data collection and analysis • Guyatt GH, Sackett DL, Cook DJ. Users’ guides to the medical
often occur in an iterative process. Data are initially collected from a literature. II. How to use an article about therapy or prevention.
predetermined number of participants, and analysis of patterns and con- B. What were the results and will they help me in caring for
cepts generates theory that informs additional data collection. Ideally, my patients? Evidence-Based Medicine Working Group. JAMA.
this process continues until no new themes emerge with additional data 1994;271(1):59-63.
collection. Thoroughness of data collection is often assessed by whether • Sevransky JE, Checkley W, Martin GS. Critical care trial design
or not the study has reached this point of “theoretical saturation.” and interpretation: a primer. Crit Care Med. 2010;38(9):1882-1889.
Additional evaluation of the validity of a qualitative study should
include careful review of the analysis methods. In contrast to quantita- • Spragg RG, Bernard GR, Checkley W, et al. Beyond mortality:
tive data analysis, qualitative data analysis utilizes inductive reasoning, future clinical research in acute lung injury. Am J Respir Crit Care
withholding the application of predetermined theories in order to allow Med. 2010;181(10):1121-1127.
new ideas or hypotheses to emerge from the data collected. The primary • Szklo M, Nieto FJ. Epidemiology—Beyond the Basics. Sudbury,
goal of qualitative analysis is interpretive—understanding responses and MA: Jones and Bartlett; 2004.
behaviors in context of the social environment in which they take place. 36 • Tomlinson G, Detsky AS. Composite end points in randomized
Qualitative methods should be reviewed no less critically than quan- trials: there is no free lunch. JAMA. 2010;303(3):267-268.
titative methods. Investigators should report how their data were coded
and how many persons were involved in the analysis process. Analysis
should be assessed for interrater reliability, where possible. Investigators
should describe a process of data “triangulation,” in which multiple REFERENCES
sources of information are used to corroborate findings. Triangulation
may occur through investigator triangulation, with multiple investigators Complete references available online at www.mhprofessional.com/hall

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