Why Rapport Seems Challenging to Define and What to Do About the Challenge

I conceived this project on August 20, 2021, and planned to include the literature published between August 16, 2021, and January 18, 2022 (see preregistration: https://osf.io/2f5ts). But I expanded the timeline to January 22, 2023, because time constraints prevented me from commencing the review on the intended start date. The expansion was necessary, given the goal of highlighting a contemporary issue.

Like Neequaye and Mac Giolla (2022), the key search term was “Rapport”, which was complemented with auxiliaries to assist in flagging publications within this review’s scope. The formal search strategy was: Rapport AND “Investigative interview*” OR Suspect* OR Eyewitness* OR “Police” OR “Interrogation” OR “Cognitive interview” OR “PEACE model” OR “Intelligence gathering” OR “NICHD”. I complemented the formal search strategy with a Google Scholar alert.

The search returned 23 publications, and I examined the full text of the search results, not just abstracts or keywords. Three articles were excluded because examining rapport was tangential to their aims, and one article was not on investigative interviewing. Nineteen publications underwent the review, and I extracted four elements for analysis using the procedure outlined below.

Element-1 was whether a publication explicitly invoked the assertion that rapport is crucial in investigative interviewing. Under Element-2, I highlighted whether the authors mentioned that rapport was challenging to define.

I extracted definitions (Element-3) using Neequaye and Mac Giolla’s (2022) protocol. Definitions comprised the predicates of sentences or parts of a publication’s text that explicitly told readers what the authors meant by rapport.

Then I examined the nature of those definitions, focusing on the presence or absence of real definitions (Element-4). If the authors described their definition using dissociation, I noted it as a presence of a real definition—if the definition appeared to offer what the authors believed is the correct description of rapport. Dissociation entails positing what a term is—arguing for indispensable characteristics of a presumed thing—rather than what a word means—how stakeholders use a term. Dissociation is enacted by implicitly or explicitly claiming that some definition X—with attribute P_(1-n)—is the true or correct instance of a term T. And other definitions Y are deficient in explicating T. A dissociative definition, essentially, argues that the criterion for correctly flagging X is P_(1-n). See Schiappa (1993) for an extensive discussion on dissociation.

I ensured that dissociation was identified via a perspective-independent method that avoids recapitulating an attempt to introduce a definition. Thus, the primary verbs in sentence predicates bringing readers to discern authors’ preferred definitions did not count toward flagging dissociation. For example, “we define rapport as”; “rapport is”;”rapport refers to”; “rapport indicates—something”, and something is the definition.

Markers of dissociation comprised auxiliaries further describing the nature of a proposed definition. Such auxiliaries included: (a) adverbs and adjectives within a definitional sentence—for example, rapport is typically described as or broadly defined as something, something being the definition; and (b) discussions aimed at elaborating on a definition.

This results presentation aims at facilitating clarity. A supplemental table provides all the extractions in one snapshot and the excluded publications: https://osf.io/u7a62.

The idea that rapport is pivotal in investigative interviewing was unanimous. Authors expressed that sentiment explicitly or alluded to rapport’s importance by noting its benefits (see supplemental table). Examples include “rapport is a central component of an information-gathering approach (Brimbal et al., 2021)” and “rapport has been […] associated with a range of beneficial outcomes (Gabbert et al., 2021)”.

Despite the univocality of rapport’s significance, most authors said there was trouble defining the term (13/19 publications ~ 70%). That challenge was evident when examining the presence and absence of definitions. Approximately 52% of the publications (10/19) either did not define rapport (2/19) or posited multiple definitions (8/19), making a definitional preference impossible to detect (see Table 1).

The remaining publications, 48% (9/19), provided a single focal definition, allowing an analysis of their nature. All but one of those publications that specified definitions (8/9) came with some form of dissociation. Thus, most of those publications attempted to posit a real definition of rapport in investigative interviewing. The dominant dissociation style (Dissociation-1 in Figure 1) was implemented five times, whereby authors suggested that their definitional preference characterized the essential component(s) of rapport. Crough et al. (2022) noted that their definition precisely explicated the nature of rapport in investigative interviewing. Others mentioned that their definition is synonymous with rapport (Marin & Gabbert, 2022); is considered to be rapport (Foster et al., 2022); and the typical (Nahouli et al., 2022) or a complete (Nahouli et al., 2022) description of rapport.

The other dissociation styles (Dissociation-2 and -3 in Figure 1) appeared twice, respectively. All the invocations of Dissociation-2 comprised authors pitching a broad definition, suggesting it encapsulates any conceivable status quo of rapport’s meaning (Brimbal et al., 2021; Hoekstra & Verhoeven, 2021).

The other form of dissociation authors used was proposing new definitions to improve existing ones (Dissociation-3). Gabbert et al. (2021) proposed “professional rapport” to distinguish rapport in investigative interviewing from rapport in other social contexts. The authors indicated that intentionality (when facilitating a positive interaction) was the distinctive component. Crough et al. (2022) posited “interrogative rapport”, arguing that it improves on professional rapport (viz., Gabbert et al., 2021). Crough et al. (2022) noted that interrogative rapport accounts for the adversarial function of rapport in suspect interviewing.

In all, the findings indicate that the ambiguity surrounding the definition of rapport persists (see also Neequaye & Mac Giolla, 2022). Half of the most recent publications did not specify a focal definition. And publications that specified a definition appeared to posit a real definition (see Figure 1). I examined the consistency between those definitions by inspecting the attributes that characterized them. Neequaye and Mac Giolla (2022) flagged the attributes authors typically use when defining rapport: positivity, mutuality, communication, successful outcomes, trust, and respect. Those attributes guided my inspection strategy.¹

All but one of the nine definitions indicated that positivity characterizes rapport—positivity being an interaction that participants might find pleasant. But the definitions came with different attributes than positivity (see Table 2). For example, Brimbal et al.’s (2021) definition included the attributes positivity, respect, and trust—while Hoekstra and Verhoeven (2021) defined rapport with positivity and mutuality (of communication).

Table 2 makes it evident that the definitions are not identical: they ascribe rapport with different attributes. Which of those supposedly real definitions should be the standard reference when assessing construct validity? There is currently no basis to give any definition the standard reference status. That is why the sentiment “rapport is difficult to define” remains a refrain in the literature. The expression—rapport—is ingrained in investigative interviewing research. A suggestion to discontinue its use would go unheeded. But the literature needs a univocal definition to maintain objectivity for construct validity’s sake.

Next, I expand on the pitfalls of pursuing a real definition of rapport and why a nominal definition offers a pragmatic solution, given the literature’s state.

It is incontrovertible that the notion of rapport is ambiguous by default. Other research domains, not just investigative interviewing, use rapport in different senses. For example, analysts in the field of communication research have long since lamented that rapport encompasses a wide variety of relational formulations (e.g., Jorgenson, 1992). The tendency for the word to elicit different interpretations disguises the challenge that troubles us as one real definition can solve—because real definition presents a false hope of bringing objectivity. In what follows, I will explain why nominal definition is a more objective approach and can better address the challenge of restoring clarity better than real definition can.

Nothing can provide a literal point of comparison to ascertain the veracity of any given definition. As Abelson (1967) notes, if we cannot observe an abstract notion, we cannot establish that a definition necessarily captures that idea. Analysts cannot implement a perspective-independent method to verify whether any corresponding real definition of rapport, in fact, resembles something in the ether called rapport. That mirage leads well-intentioned research projects to continue stipulating real definitions, hoping that they might capture what rapport truly is. Such pursuits of real definition have riddled the literature with numerous definitions, rendering the word rapport meaningless in the investigative interviewing literature. According to the review by Neequaye and Mac Giolla (2022), at least 22 unique definitions exist.

Nominal definition will rectify the limitations of inconsistency with which real definition has plagued the literature. Stakeholders must determine what the word rapport is to mean as far as investigative interviewing is concerned. And the nominated definition must outline the values and properties stakeholders consider crucial and why. Examples of values include—Should rapport concern the human rights of interviewees? Should the word refer to congeniality? Or should it cover a range of set values? And the matter of property arises when considering directionality.² Should rapport concern attributes that naturally emerge between interactants (e.g., “the subjective experience between the interviewer and the interviewee”: Foster et al., 2022)? Or should rapport focus on attributes of the interviewer’s approach to conducting an interview (e.g., “[A] temporary working relationship created strategically by the interviewer: Crough et al., 2022”)? Let us abandon the fiction that we can arrive at a rapport definition without acknowledging that definitions legislate what stakeholders consider acceptable in a given context. Whenever authors posit a definition, they prescribe ideals they believe should characterize the interaction between an interviewer and interviewee. Consider the following definitions.

According to Tamm et al.’s (2021) definition, interpersonal trust, respect, understanding, and acceptance are the critical ideals that should characterize rapport. And Nahouli et al. (2022) subscribe to harmony, empathy, and connection. We do the literature a disservice when we present such recommendations as though they are facts, like the date of a historical event. Definitions are choices—temporary agreements about how language users understand terms (Robinson, 1963; Schiappa, 1993). And a rapport definition should be approached accordingly—a temporary agreement on what investigative interviewing researchers and practitioners want rapport to mean.

By temporary agreement, I do not mean to suggest that we should entertain multiple nominal rapport definitions at once. Multiple nominal definitions would likely perpetuate ambiguity. An essential advantage of nominal definition is that the approach is pragmatic and stands a better chance of leading to consensus about what stakeholders want rapport to mean. I use the phrase temporary agreement to emphasize that stakeholders can continue to debate any nominal definition that achieves consensus status, subjecting it to scrutiny and necessary adjustment to improve. That ethos of nominal definition offers the advantage real definition lacks when defining abstract concepts. Real definition assumes to have flagged an objective thing, stifling further debate. But nominal definition is a temporary agreement that leaves room for refinement if necessary. That flexibility of nominal definition makes it more amenable to facilitating consensus.

The recommendation to nominate a rapport definition likely to embody consensus ideals might invite objections. I will flag and address some of those counterarguments that can arise. Note that the following discussion concerns the investigative interviewing literature.

A critic might say: “the call to simply nominate a single sense to use the word rapport is arbitrary”. The objective way to arrive at a definition is by some form of scientific analysis or synthesis with rigor.” For example, Duke (2013) reviewed the literature to identify attributes representing rapport.³ That counterargument supposes stakeholders must conduct experiments, survey experts, or review the relevant literature to define rapport.

The objection just described fails to distinguish a method of formulating a definition from the purpose of designating that definition. Stakeholders might be unsure of consensus ideals or want to ascertain those ideals. Experiments or literature reviews could assist in arriving at ideals stakeholders would agree with—to form an acceptable definition. But let us not lose sight of the fact that analysis or synthesis are methods to achieve the objective of uncovering ideals. Whatever method one chooses to flag ideals will necessarily produce a choice—a nominal definition. When we fail to recognize the distinction between method and purpose, we allow the illusion that certain methods generate real definitions when, in truth, methods are tools that assist in nominating definitions.

One could ask this question to disagree with a pragmatic approach to a rapport definition. “How can we prove we have captured rapport if we nominate a definition?” As discussed, stakeholders can use scientific methods to assist with a nomination. The idea that one needs to prove a definition captures some abstract notion is yet another illusion vitalized by the folly of real definition (Robinson, 1963). Let us not forget that there is no literal point of comparison to ascertain that one definition is more rapport-like than any other. Of course, different people might find some definitions more reasonable than others. Such disagreements come down to preference, not objective reality.

The charge to prove a rapport definition implicitly suggests that the word naturally denotes a single sense. But it is evident that rapport elicits different interpretations from various authors. The objective to demonstrate that any definition is the best copy of something called rapport cannot succeed when no literal point of comparison exists. The issue to prove is whether a choice of nominal definition can or has achieved consensus status among a community of language users. Real definitions of rapport pitch themselves as descriptions of objective reality—but such definitions cannot be tested to ascertain their verisimilitude, given rapport’s abstractness. Conversely, nominal definitions would indicate the current preference of language users—whether stakeholders hold such preference can be verified.

The primary goals of investigative interviewing comprise the need for interviewers to conduct themselves ethically and elicit information relevant to an investigation (e.g., Brandon, 2014; Vrij et al., 2017). It is essential not to mistake those objectives as definitions of rapport or include those goals in a definition. Such oversight invites circular and unfalsifiable hypotheses, and definitions with that feature already exist in the literature. For example: “a working relationship between operator [an interviewer] and source [an interviewee] based on a mutually shared understanding of each other’s goals and needs—that can lead to successful actionable intelligence or information [emphasis added] (Kelly et al., 2013)”.

Two blind spots accompany definitions with the limitation just described. (1) They prevent analysts from designing the appropriate studies to examine rapport’s correlates. That limitation makes it impossible to refute rapport’s presumed effects. Suppose a manipulation fails to generate the outcomes contained in a definition, like actionable intelligence, as included in Kelly et al.’s (2013) definition. Then, one could claim the operationalization insufficiently instantiated rapport. That loophole consistently shifts the goalpost. Analysts can never question the definition’s ability to produce the correlates of interest. (2) Definitions containing circular claims make an idea necessary before analysts can examine whether that importance is warranted. Definitions claiming that rapport makes interviewing ethical or elicits relevant information well-nigh conclude research on rapport: there is nothing left to examine.

This article draws attention to the ambiguity of rapport in the investigative interviewing literature via a conceptual analysis explaining the limitations of pursuing real definitions. The question “what is rapport?” continues to baffle researchers and practitioners due to the proliferation of and search for real definitions. And because there is no literal point of comparison, different authors use the word in different senses, assuming (implicitly or explicitly) they have captured the real thing. We can escape that quagmire using a practical approach via a nominal definition, which embodies ideals or values the majority of stakeholders will accept. Such a definition can be achieved while maintaining scientific rigor. Stakeholders must nominate a single sense in which to use the word rapport.

A critic might take issue with this review’s methodology with this objection: some publications are missing due to the focus on the most recent articles. To the best of my knowledge, this review includes all articles published on rapport in investigative interviewing within security settings (August 2021 – January 2023). Besides, Neequaye and Mac Giolla’s (2022) review highlights similar ambiguities in the remainder of the literature. Even if one grants the unwarranted concession that this review misses critical publications, the limitation this review flags would still be concerning. Multiple and different definitions continue to drive most of the latest research, perpetuating conceptual ambiguity. Relatedly, one could argue that this review should have analyzed methods authors use in measuring rapport. But such an analysis would be a fruit of a poisonous tree. I focused on definitions because definitional limitations call measurement into question by default (e.g., Flake & Fried, 2020). It is challenging, if not impossible, to offer an objective or fair analysis of suited methods and construct validity if confusion surrounds the term stakeholders want to measure.

The question “what is rapport?” will cease being a headache if stakeholders make a concerted effort to arrive at a consensus definition. Such consensus will provide a standard to assess operationalizations claiming to examine rapport and its correlates. A nominal definition stands the best chance of bringing the clarity the investigative interviewing literature needs on rapport.

There are no conflicts of interest to declare.

All data supporting the findings in this research are publicly available publications, and the present manuscript contains the pertinent aspects.