Interviews: Selection and Saturation
The interview phase of our study is based on a grounded theory approach, which holds that researchers conduct interviews until reaching a saturation point where no new themes emerge. The core idea of grounded theory is that results emerge out of, and resonate with, the knowledge frameworks of the participants themselves. Rather than using participants to confirm or disprove a pre-selected theory, new theory is generated from the information, views, and experiences that they share.
Grounded theory is underpinned by a robust scholarly literature, with scholars examining its conceptual dimension, its methods and techniques, and its limits (Birks and Mills 2023; Bryant and Charmaz 2010; Levitt 2021). Where grounded theory falls short in terms of generalizable conclusions, it more than makes up for in the production of richly informed knowledge emerging from the subjects of the study. For this reason, it is particularly useful when combined with other methods, as we do in this study (Creamer 2021).
We will use a semi-structured instrument to guide conversation, which allows us to pull out themes of interest to our study, but which also provides space for participants to raise additional issues or cover unforeseen material. We will conduct around 20 such interviews in each of the three cities, for a total of 50-60 interviews. Participants will be compensated at the rate of USD 50 for the generous gift of their time.
The first principal for selecting participants is based on location and population. We have identified one neighborhood in each city for our focus (see Field Note on Neighborhood Selection). As this is primarily a study of people's perceptions, experiences, and ideas, we will interview people who live in these neighborhoods since they will have the required expertise and insight.
The main approach for selection is non-random purposeful sampling. This will allow us to generate an information-rich outcome to inform theory. Generalization is not the goal of this study; rather, we are interested in depth of understanding that emerges from participants' stories. For this reason, our recruitment method will rely first on critical case sampling, which Onwuegbuzie (2007, 111–12) describes as selection that "brings to the fore the phenomenon of interest such that the researcher can learn more about the phenomenon than would have been learned without including these critical cases." In our case, the phenomenon of interest is residential life in landscapes characterized by high rates of vacancy and abandonment. Recruitment will rely secondarily on a snowball sampling, where participants suggest one to three additional people to interview, thereby immersing us in a salient network.
There is some discrepancy in the literature regarding the optimal number for a qualitative study based on grounded theory. Francis et al (2010) sugges that on average 17 interviews are needed before saturation, depending upon the complexity of the study. Hagaman and Wutich (2017) have found that their studies require anywhere from 20 to 40 interviews to produce relevant findings. Hennink, Kaiser, and Marconi (2017) find that 16-24 interviews usually suffices to achieve a saturation point. For Nelson (2017), the quantity is less important than the quality, which should be based on conceptual depth.
For coding we will draw primarily on approaches that emerge out of grounded theory, detailed by Johnny Saldaña's Coding Manual for Qualitative Research (2021). We will develop a separate Field Note entry on Coding soon.
Birks, Melanie, and Jane Mills. 2023. Grounded Theory: A Practical Guide. Thousand Oaks, CA: SAGE Publications Ltd.
Bryant, Antony, and Kathy Charmaz, eds. 2010. The SAGE Handbook of Grounded Theory: Paperback Edition. Los Angeles: SAGE Publications Ltd.
Creamer, Elizabeth G. 2021. Advancing Grounded Theory with Mixed Methods. New York, NY: Routledge.
Francis, Jill J., Marie Johnston, Clare Robertson, Liz Glidewell, Vikki Entwistle, Martin P. Eccles, and Jeremy M. Grimshaw. 2010. “What Is an Adequate Sample Size? Operationalising Data Saturation for Theory-Based Interview Studies.” Psychology & Health 25 (10): 1229–45.
Hagaman, Ashley K., and Amber Wutich. 2017. “How Many Interviews Are Enough to Identify Metathemes in Multisited and Cross-Cultural Research? Another Perspective on Guest, Bunce, and Johnson’s (2006) Landmark Study.” Field Methods 29 (1): 23–41.
Hennink, Monique M., Bonnie N. Kaiser, and Vincent C. Marconi. 2017. “Code Saturation Versus Meaning Saturation: How Many Interviews Are Enough?” Qualitative Health Research 27 (4): 591–608.
Levitt, Heidi M. 2021. Essentials of Critical-Constructivist Grounded Theory Research. Washington, DC: American Psychological Association.
Nelson, James. 2017. “Using Conceptual Depth Criteria: Addressing the Challenge of Reaching Saturation in Qualitative Research.” Qualitative Research 17 (5): 554–70.
Onwuegbuzie, Anthony J., and Nancy L. Leech. 2007. “A Call for Qualitative Power Analyses.” Quality & Quantity 41 (1): 105–21.
Saldaña, Johnny. 2021. The Coding Manual for Qualitative Researchers. Fourth edition. Thousand Oaks, CA: SAGE Publications Ltd.