This paper concerns the role of data in interpretive qualitative theory building. A great extent of empirical studies in qualitative research (arguably, the majority of them) consists of studies where a theory emerges from the analysis of the data. In many cases, qualitative researchers describe emergent theories as interpretations. Itis both intuitive and typically assumed by researchers that (a) the emergent theory or interpretation must have some credibility, and that (b) this credibility is in some way a function of the quality and volume of available observations. An example of this attitude is the volume of publications discussing how many interviews or qualitative observations are enough to draw a valid conclusion. Another example comes from the use that some researchers make of the concept of saturation (which originally was meant to indicate the point at which the data cannot provide further insight about the theory) as a way to indicate that the observation base is sufficient to support the emergent theory or interpretation (Lowe et al 2018). Recently, several quantitative measures of saturation meant to estimate the relation between data and interpretation have been proposed as a means to improve the transparency of this way of reasoning about support (Lowe et al 2018). This refects claim (b), since the fact that an emergent theory saturates the data is taken in this case to be an indication both of the support that the data provided to the theory and of its credibility. In order to assess the rationale for these approaches, I consider emergent theorization from a more abstract methodological point of view. From this perspective, qualitative methodologists have argued that the kind of reasoning characterizing these studies fits the inferential scheme called selective abduction(Richardson & Kramer 2006; Lipscomb 2012). The emergent theory or interpretation is supposed to explain the data, several interpretations are often (but not always)compared and some criteria are assumed to be necessary in order to establish which interpretation is the best among the available candidates. Although there is a vast literature concerning selective abduction, its justification, and its use in science, the relationship between the available data and the selection criteria has not been discussed in detail. Among the few examples of this discussion, Niiniluoto (1999)presents different comparative criteria for the quality of the abduced theory that include the data as a parameter. Following this methodological perspective, if measures of saturation such as those proposed by Lowe et al. estimate the support that data provides to interpretations, then it must be possible to compare the saturation resulting from different emergent theories as a selection criterion. However, I argue that these approaches do not satisfy any of the different comparative criteria presented byNiiniluoto.Therefore, I suggest an alternative approach, consisting of the construction of qualitative, theoretically informed, ordinal evaluations of observation base and theory. I propose these evaluations to be i) the ‘surprisingness’ of the observation, ii)the overall credibility of the interpretation in relation to the existing literature, and, finally, iii) the plausibility of obtaining the same observation if the interpretation were correct. Basic Bayesian reasoning is then applied to (i)-(iii) to evaluate the credibility of the emergent theory in relation to the available observations. This approach has several advantages. First, it fits Niiniluoto's conceptualization, which provides this approach with rational justification. Secondly, evaluations (i)-(iii)are intuitive, sensitive to background knowledge, and based on judgments that are commonly used in the literature on qualitative methods. My conclusion is that it is correct to conceptualize qualitative emergent theorizing as selective abduction and that researchers are correct in arguing that the credibility of their interpretations is a function of the available observations. However, I disagree that the comparative criteria for selection require quantitative measures of support. Theory-based, qualitative ordinal assessments are sufficient to evaluate the credibility of emergent theories.

REFERENCES

Lipscomb, M. (2012), Abductive reasoning and qualitative research. NursingPhilosophy, 13: 244-256. doi:10.1111/j.1466-769X.2011.00532.x

Lowe, A., Norris, A. C., Farris, A. J., & Babbage, D. R. (2018). Quantifying thematic saturation in qualitative data analysis. Field Methods, 30(3), 191-207.

Niiniluoto, I. (1999). Defending abduction. Philosophy of science, 66, S436-S451.

Richardson, R., & Kramer, E. H. (2006). Abduction as the type of inference that characterizes the development of a grounded theory. Qualitative Research, 6(4),497–513. https://doi.org/10.1177/1468794106068019