Evidence-Based Practice: 7 Myths of Qualitative Research Busted

  •   April 30, 2015
  •  Leanne Loranger, PT

Physiotherapists and others working in biomedical sciences are typically quite comfortable reading quantitative research, but what if your literature search has returned qualitative research studies? How do you know if the research is of good quality? Do you throw out the qualitative studies and focus on results that are quantifiable?

To be clear, qualitative research involves looking at non-numerical data and is usually used to gain an understanding of motivations, opinions, etc. Quantitative research uses numerical data to quantify a problem and generate statistics.

Since qualitative research was once the domain of social scientists,1 you may be uncertain of how to appraise this type of literature. In fact, the science of critically appraising a qualitative paper is not as clear cut as that of quantitative research, so you will need to be careful when deciding if the literature you have found is worth reviewing.

Myth #1: Qualitative methods of research aren’t rigorous.

Fact: Common qualitative research methods include interviews, focus groups, direct observation and document review.2 Well designed qualitative research studies should provide clear information about the methods used in the study with enough information to tell the story of how the research was conducted.1 As with any form of research, there are accepted methods for conducting a focus group, an interview or any other type of qualitative research.1 When reading qualitative research, look for information about the researcher’s experience. On some level, the researcher is acting as an instrument of data collection and is closely involved with the subjects. Being credible, knowledgeable and experienced with accepted methods is therefore critical.2

Myth #2: Random sampling is the only way to gather a group of research subjects.

Fact: Random sampling may help ensure that the results of a quantitative study are generalizable, but in qualitative research random sampling is not desired. Purposive sampling is the norm.1 If you find a qualitative study in which the researchers describe a random sample, move on to the next study.

Qualitative researchers use a process called progressive focusing to test their assumptions and develop a deeper understanding of a group or an experience.1 This means the researcher starts with a question but may not have a hypothesis of what is happening. As data is gathered, the researcher may notice a trend that leads them to refine their research question and gather more subjects who have a particular characteristic,1 purposefully selecting these people to be part of the study.

Myth #3: The researcher’s opinions and perspective have no role in research.

Fact: A key component of qualitative research is recognizing that researchers bring their own unique perspective to the study. A mark of a high-quality study is for the researcher to identify their own perspective and how this perspective may impact the research and their interpretation of the findings.1,2 In qualitative research this is called reflexivity.1 When judging the quality of a study, look for some information about the researcher’s perspective. Claims of being unbiased, neutral or having no opinion should be viewed as red flags.

Myth #4: Researchers must be ‘blinded’ and removed from their subjects in order for the research they produce to be valid and reliable.

Fact: In a quantitative study where an experiment is being performed, the researcher needs to remove potential sources of bias in order to avoid skewing the results and this includes remaining removed from the subjects enrolled in the study. In contrast, with qualitative research it is not uncommon for researchers to directly interact with research subjects in order to understand a particular culture or what it is like to experience a particular condition.2 Researchers may need to develop relationships with their subjects in order to discuss the subject’s perspective. In this way, the researcher becomes an instrument of the research.2

Myth #5: You should find a calculation that will tell you that enough subjects have been included in the study for the information to be generalisable.

Fact: In qualitative research there is no set minimum number of subjects that can be calculated with a formula. Sample size is determined by the number of subjects required to get redundant information.2 In other words, the research continues until no new information about the research question is uncovered. What makes qualitative research generalizable is its validity (more on validity below).1

Myth #6: Qualitative research findings relate to a set group of participants, they can’t be valid and generalized to a larger group of patients.

Fact: In qualitative research, validity is sought by having more than one source of data that helps the researcher to understand what is really going on in a situation.1,2 A high-quality study is one where data has been triangulated by including more than one type of information in the analysis to ensure a complete picture of the phenomenon. The other factor that helps with validity and the transferability of the findings is whether or not the subjects have been clearly described by the researcher.2 This allows you to assess how similar to your own patient group the research subjects are.

Myth #7: There’s no way for qualitative research to be unbiased if the sample isn’t random and the researchers aren’t blinded.

Fact: Bias can be limited in qualitative research2 by:

  1. Having researchers reflect on their research and their own perspective
  2. Having colleagues audit the decision making and analysis processes
  3. Participant checking to assure that the conclusions drawn by the researcher are confirmed by the subjects

The use of these methods helps to ensure the trustworthiness of the study and its conclusions.

Since, in the words of Trish Greenhalgh, qualitative research “is now increasingly recognized as being not just complementary to but, in many cases, a prerequisite for the quantitative research with most of us… are more familiar”1 it is imperative that physiotherapists become more familiar with how to read and evaluate the quality of qualitative research. 

As always, the focus of this series is to address evidence-based practice related questions and to create a dialogue between Physiotherapy Alberta and members of our profession, with the goal of facilitating evidence based practice and knowledge translation. Our intent is not to be the expert on the topic, but to be a knowledgeable voice in the discussion. We encourage you to read this and other articles in the series, discuss them with your colleagues and to share your comments via email at lloranger@physiotherapyalberta.ca, on twitter @PTAlberta, or on our Facebook page.


  1. Greenhalgh T. Why read papers at all? How to read a paper: The basics of evidence-based medicine. Hoboken: Wiley-Blackwell BMJ Books, 2010.
  2. Law M, MacDermid J. Introduction to evidence-based practice. Evidence-based rehabilitation: A guide to practice. Thorofare: SLACK Incorporated. 2008.