NOTE: Melanie Rügenhagen was co-author of this entry.
Replication is difficult to apply to qualitative studies in so far as it means recreating the exact conditions of the original study — a condition that is often impossible in the real world. The key question then becomes: “how close to the original must a replication be to validate an original experiment?” (Seadle, 2018)
This question is particularly important because of the widespread belief that only quantitative research is replicable. Leppink (2017) writes:
“Unfortunately, the heuristic of equating a qualitative–quantitative distinction with that of a multiple–single truths distinction is closely linked with the popular belief that replication research has relevance for quantitative research only. In fact, the usefulness of replication research has not rarely been narrowed down even further to repeating randomised controlled experiments.” (Leppink, 2017)
Dennis and Valacich (2014) suggest three categories for replication studies, only one of which is “exact” (see the column from 23 May 2018). The conceptual and methodological categories are both relevant to qualitative research, because the participants and the context can vary as long as the replication tests the inherent goals and concepts, as well as the methodological framework of the original. In other words, successful qualitative replications can provide a confirmation of the hypotheses at a higher level of generalisation. Even when the specific contexts change. What matters is that the concepts and outcomes remain constant. As Polit and Beck (2010) write:
“If concepts, relationships, patterns, and successful interventions can be confirmed in multiple contexts, varied times, and with different types of people, confidence in their validity and applicability will be strengthened.” (Polit & Beck, 2010)
These authors support the use of replication in qualitative research, and argue that replication is the best way to confirm the results of a study:
“Knowledge does not come simply by testing a new theory, using a new instrument, or inventing a new construct (or, worse, giving an inventive label to an old construct). Knowledge grows through confirmation. Many theses and dissertations would likely have a bigger impact on nursing practice if they were replications that yielded systematic, confirmatory evidence—or if they revealed restrictions on generalized conclusions.” (Polit & Beck, 2010)
How can one ensure that the evidence is systematic? Leppink (2017) suggests that researchers in all kinds of studies have to decide when they no longer need more data in order to answer their research question and calls this concept saturation.
It is important to remember that qualitative research normally does not generalise about results beyond the community involved in the samples, which sets a very limited and specific context for the research question. At some point researchers need to decide when their question is answered, stop their inquiries, and come to a conclusion. Leppink (2017) writes:
“If saturation was achieved, one might expect that a replication of the study with a very similar group of participants would result in very similar findings. If the replication study leads to substantially different findings, this would provide evidence against the saturation assumption made by the researchers in the initial study.”
Saturation means that the answer to a research question is complete, and becomes a core element of the “systematic, confirmatory evidence” (Polit & Beck, 2010) for analyzing validity. It can also help to provide metrics by uncovering the degree to which a study may be flawed or even intentionally manipulated.
Nonetheless there are barriers. While a range of studies based on the same concepts and methodology can lead to insights about whether a phenomenon is true, not knowing exactly how the original researchers conducted their studies may make replication impossible (Leppink, 2017). This makes describing the methodology particularly important.
None of this is easy. Replication studies remain a stepchild in the world of academic publishing. Gleditsch and Janz (2016) write about efforts to encourage replicating their own research area (international relations):
“Nevertheless, progress has been slow, and many journals still have no policy on replication or fail to follow up in practice.”
The problem is simple. There is no fame to be gained in showing that someone else’s ideas and conclusions are in fact correct, and it is hardly surprising that ambitious researchers avoid doing replications, especially for qualitative research, where the risk of failing is high and succeeding only makes readers think that the original study was done well.
Gleditsch, Nils Petter, and Nicole Janz. 2016. “Replication in International Relations.” International Studies Perspectives, ekv003. Available online.
Polit, Denise F., and Cheryl Tatano Beck. 2010. “Generalization in Quantitative and Qualitative Research: Myths and Strategies.” International Journal of Nursing Studies 47 (11): 1451–58. Available online.
Michael Seadle. 2018. “Replication Testing.” Column on Information Integrity 2/2018. Published on 23 May 2018. Available online.
Leppink, Jimmie. 2017. “Revisiting the Quantitative–Qualitative-Mixed Methods Labels: Research Questions, Developments, and the Need for Replication.” Journal of Taibah University Medical Sciences 12 (2). Elsevier B.V.: 97–101. Available online.
Dennis, Alan R, and Joseph S Valacich. 2014. “A Replication Manifesto.” AIS Transactions on Replication Research 1 (1): 1–5.