Mind the [research] gap

Tara Brabazon (2025) talked about the SOCK - the significant contribution to knowledge - and the research gap in a video last year, citing a few papers which I had not formerly encountered. This idea of a taxonomy of the research gap I found particularly interesting, so I scuttled off to have a gander at the papers cited. To my delight I found that there are several types of research gaps, arising in three waves of taxonomy: Robinson, et al. (2011); Mueller-Bloch & Kranz (2015); and Miles (2017). 

Let's work back from today, beginning with Miles (2017) who synthesised and consolidated the work of Mueller-Bloch & Kranz (2015) and Robinson et al. (2011) into a broader taxonomy of seven core types of research gap: evidence; knowledge; practical-knowledge (which I think of as the 'practice' gap); methodology; empirical; theoretical; and population, as follows (Miles, 2017):

1. Evidence Gap: when new research findings contradict our currently accepted world view. Results from individual studies may look sound, but when examined from a theoretical perspective, they no longer hold up so well (p. 3)
2. Knowledge [Void] Gap: the most common literature review gap, because desired topic findings don't yet exist. This can arise when study results don't match researcher expectations (p. 4)
3. Practical-Knowledge Gap: or the 'practice' gap (i.e. practice is different to theory or documented process). Significant in applied fields like education, social work, and healthcare, this gap happens when practice differs to espoused behaviour - or to established research findings (p. 4).
4. Methodological Gap: This deals with conflicts that arise because a specific methodology has dominated a field, potentially influencing or distorting research outcomes. A gap is identified when a variation in research methods is necessary to generate new insights or avoid these distortions (p. 4).
5. Empirical [Void] Gap: This type of gap exists when prior research findings or propositions have been stated but never empirically verified or evaluated through rigorous study.
6. Theoretical Gap: This occurs when there is a lack of theory, or when existing theories need to be applied to new research issues to generate fresh insights. It can also involve a conflict where multiple theoretical models attempt to explain the same phenomenon, creating a gap in understanding which is superior.
7. Population Gap: This refers to populations that are under-represented or under-researched in the existing evidence base, often due to factors like age, gender, race, or disability.

Rolling the clock back, another way at coming at the research gap is that used by Robinson et al. (2011) to focus on the specific reasons why the evidence fails to convince, often using the PICOS (Population, Intervention, Comparison, Outcome, Setting) framework from the health sector (similar to the PICO framework, I wonder? Read more here); and largely for quantitative research, judging by the language used in the article. The four research gap reasons  proposed are (Robinson et al., 2011):

1. "Insufficient or imprecise information": this is when there are too few studies, or if sample sizes are too small to allow us to make the conclusions we wish to draw (p. 1327)
2. "Biased information": this is when our study designs is too flawed to gather good evidence, or selective outcome reporting - e.g. 'p hacking' - occurs (p. 1327)
3. "Inconsistency or unknown consistency": this is when different studies effect sizes or results are contradictory or effects are too variable (p. 1327)
4. "Not the right information": ah - studies that have not asked suitable populations, or haven't asked the key question or questions, or are trying to get to long-term effects with a short-term study (Robinson et al., 2011, p. 1327).

As previously mentioned, the initial models arose out of quantitative healthcare research, but can now be used across many disciplines and in qualitative research. 

I found this quite an interesting way of thin-slicing the issues.

Sam

References:

Brabazon, T. (2025, July 24). Post 104 - The research gap [video]. YouTube. https://youtu.be/q_8qK_mOxOw

Miles, D. A. (2017, August). A taxonomy of research gaps: Identifying and defining the seven research gaps. In Doctoral student workshop: finding research gaps research methods and strategies, Dallas, Texas (Vol. 1, pp. 1-10). Academia. https://www.academia.edu/35505149/ARTICLE_RESEARCH_A_Taxonomy_of_Research_Gaps_Identifying_and_Defining_the_Seven_Research_Gaps

Muller-Bloch, C., & Kranz, J. (2015). A Framework for Rigorously Identifying Research Gaps in Qualitative Literature Reviews [research paper]. Thirty Sixth International Conference on Information Systems (ICIS), Fort Worth, USA, December 13-16, 2015. https://aisel.aisnet.org/icis2015/proceedings/ResearchMethods/2/

Robinson, K. A., Saldanha, I. J., & Mckoy, N. A. (2011). Development of a framework to identify research gaps from systematic reviews. Journal of Clinical Epidemiology, 64(12), 1325-1330. https://doi.org/10.1016/j.jclinepi.2011.06.009