Introduction

This special issue is unique. Whereas most are focused on specific topics (e.g., Technology & Marketing; Measure Validation in Marketing), this special issue is agnostic to topical domain. Instead, we called for review-based research on any topic – substantive domain, theory, or method – that is import to marketers, and for which the authors could identify important generalizations.

Review papers are “critical evaluations of material that has already been published” (Bem 1995, p. 172). They comprise approaches such as meta-analyses that provide quantitative estimates of effects, as well as qualitative reviews of published studies. As we noted in the call-for-papers for this special issue, when designing new research it is important for the scholar to have a state-of-the-art understanding of research findings (e.g., empirical generalizations) regarding their focal phenomenon.

Prior editorials (e.g., Bem 1995; Barczak 2017; Ethiraj et al. 2017) and review papers (e.g., Hanssens 2018; Voorhees et al. 2016) highlight a range of important purposes that well-done review papers can serve. As Palmatier et al. (2018; p. 2) note, not every review paper “can offer all of these benefits.” Nonetheless, key potential contributions include the following:

Outline the scope of the topical domain and overview the current state of knowledge

This benefits scholars who are new to the topic area and can broaden the perspective of a scholar who has focused their work in only a niche of the larger domain. However, reviews that provide only this benefit (i.e., that are “purely descriptive in nature,” Barczak 2017, p. 120) are of limited impact, as they do not directly provide insights that enable the field to advance.

Resolve inconsistencies across extant studies

Science advances by building on prior knowledge. Often, competing studies offer differing predictions and/or results for key relationships. A review paper can identify such inconsistencies and identify potential explanations for them. Some explanations might emerge from theory (e.g., differing or unmeasured moderating or mediating variables), while other might emerge from method (e.g., differing samples, measures, operationalizations) or even simple construct-definition differences (or ambiguities), across studies. By explaining potential reasons for inconsistent and/or competing prior results, review studies can generate new knowledge, such as new conceptual frameworks. In addition to reconciling past findings, useful conceptual frameworks offer specific guidance for future research that can extend past research in ways that help the field advance systematically in its knowledge. In a similar way, papers that review extant methodological approaches can generate insights into the relative efficacies of method choices that researchers can use to guide the designs and implementations of their future studies (e.g., Hulland et al. 2018; Sorescu et al. 2017).

Integrate and synthesize extant knowledge

Because no one governs the ever-evolving community of scholars who work in a particular scholarly domain, knowledge tends to accumulate in a piecemeal fashion. Scholars’ empirical efforts are bounded by the availability of data, so certain industries or contexts are over-represented in the body of published work, and the quality of measures of or proxies for various potential constructs varies widely. Such data-availability issues can combine with heightened expectations for quantitative rigor (and sophistication) at top-tier journals across business fields to narrow the focus of any study to smaller niche problems (Houston 2019). If a review paper can synthesize insights from these disparate studies (rather than simply review them), new ways of looking at the overall phenomenon can emerge.

Highlight gaps in the body of extant research

A review paper gains usefulness when the overarching look across extant studies allows a scholar to identify important gaps (e.g., critical research questions that have yet to be answered, critical contingencies for which prior research has not accounted) that hinder continued progress in understanding the phenomenon. One caveat: simply identifying a gap does not mean that that gap is important. For example, after several studies have consistently replicated a phenomenon, the fact that no one has examined a phenomenon in a particular industry, or country, or with a particular method is only consequential if the author can build a compelling case that received knowledge from existing studies might not hold in the new context.

Derive future research directions

With the topical domain scoped, inconsistencies across studies revealed, extant knowledge synthesized in an insight-provoking way, and specific gaps identified, a scholar is now in a unique position to shed light on how the community of scholars should advance from the current state-of-the-field. A comprehensive research agenda will include several components. It should include specific research questions whose answers will fill critical knowledge gaps regarding a phenomenon. Such questions might relate to underrepresented aspects of the phenomenon, or instead to boundary conditions and the generalizability of findings. However, a useful review might also provide guidance on construct definitions, measures, and method considerations to reduce ad hoc decisions by future scholars that would otherwise make findings across studies difficult to reconcile; this type of future research guidance helps insure that knowledge builds consistently, over time. Finally, a useful review might suggest new topical domains to which a scholar could profitably apply key insights. For example, a theory or method for understanding the decision making of consumers might be useful to scholars who study Chief Marketing Officers or other members of the top management team. This type of discussion can heighten the impact of a review study by enabling important insights to cross some of the hazy, but persistent disciplinary boundaries that otherwise restrict learnings to scholars who work with a similar method, theoretical perspective, or context.

Why this special issue?

This special issue represents one step in an ongoing editorial initiative by the Journal of the Academy of Science (JAMS) to encourage authors to craft impactful review papers and to position JAMS as a the discipline’s leading outlet for such papers. Review papers (appropriately) make up a small percentage of published papers, but when they do appear they tend to be useful to scholars in guiding subsequent research in the reviewed domain (cf. Bettencourt and Houston 2001). Yet, many review papers fail to deliver value because they provide a meandering narrative stroll through the history of research in a loosely defined domain without critical synthesis that is necessary to empower future research (Barczak 2017).

Given the value of well-done review papers, as outlined in the previous section, JAMS has been proactive in encouraging their development. In 2017, former Editor Rob Palmatier laid the plans for this special issue, inviting the two of us, John Hulland and Mark Houston, to serve as Guest Editors. In 2018, we took two further steps. First, we published a paper outlining the purpose(s), process, and structure of review articles (Palmatier et al. 2018), providing guidance on designing and conducting a review study that would enhance its ultimate usefulness to the field.

Second, JAMS sponsored a Thought Leaders’ conference, “Generalizations in Marketing: Systematic Reviews and Meta-Analyses.” Although we were a bit unsure how the market would respond to a conference that did not have a specific topical focus, the conference drew enthusiastic and worldwide participation and quickly filled. Hosted by the BI Norwegian Business School in Oslo, Norway, the conference was vibrant; despite a wide range of topics, participants were deeply engaged and sessions were highly interactive. Many of the author teams whose work ultimately appears in this special issue participated, and received valuable early feedback on their work. Our thanks to Matilda Dorotic, Francesca Sotgiu, and Stefan Worm for doing such an excellent job with the organization and execution of that event.

A note on quality and rigor

We believe that it is important to briefly revisit a few key guidelines that are critical for high-quality (i.e., rigorous and useful) review papers, because those guidelines drove the review process for the 69 papers that were submitted for consideration for this special issue.

First, to produce a useful and credible review paper, a scholar must conduct the study in a systematic way. Being systematic (versus ad hoc) in search procedures helps insure that the body of literature reviewed is as comprehensive as possible. While no review paper can be truly comprehensive, laying out clear criteria for article inclusion/exclusion and for assessing the content of those articles increases a reader’s confidence that the authors of the review have not “cherry-picked” articles or content to fit a preconceived notion or agenda. Clear, systematic procedures also enable any interested reader to replicate the study (Littell et al. 2008), whether their goal is to confirm key findings or to extend the study a decade or two later. Although systematic procedures for including articles and gleaning information from them is important, it is also critical that the authors employ state-of-the-art techniques for the analysis and reporting of their data, whether a qualitative review (see, for example, Palmatier et al. 2018 for guidance) or a quantitative review (see, for example, Grewal et al. 2018).

Second, beyond the mechanical aspects of completing a review with scientific precision, authors must then engage in two creative tasks. One creative task is that authors must synthesize the body of work that they have reviewed. Instead of providing a simple narrative description, authors must search for an effective way to group and present the reviewed studies “to guide the reader toward a better understanding of the focal phenomenon” (Palmatier et al. 2018, p. 4). There is no single “right” way to do this; for example, Martin and Murphy (2017) organize their powerful review of privacy research around differing scholarly perspectives (e.g., economic perspectives, psychological perspectives). In contrast, Sorescu et al. (2017) offer important recommendations for the future use of event-study methods in marketing by organizing their insights around various issues within the design of event studies (e.g., the definition of events; choice of sample) and the interpretation of investor-reaction results.Footnote 1

Such a synthesis provides a foundation for the second creative task, identifying significant new insights that emerge from looking across the body of scholarship (i.e., insights that are not apparent from a careful examination of any individual study or small group of studies). There is no easy, multi-step process to uncover connections and other non-obvious insights among studies; thus, this second guideline is often the most challenging to implement. There is no substitute for a process of studying, re-reading, discussing, debating, writing, gathering critical peer feedback, and refining that often takes months of hard effort after a scholar has completed the mechanical review tasks. Yet in our opinion, this process is what produces the primary value resulting from the review; the usefulness of the insights generated is what separates highly cited review papers from reviews that are largely ignored.

Overview of the articles in this issue

We are thankful to the efforts of many authors and reviewers for the work that went into creating and crafting the papers in this issue. After multiple rounds of review and revision, we are pleased to present eleven papers that individually represent diverse topics, yet collectively demonstrate the value of rigorous reviews to our discipline.Footnote 2 Table 1 organizes these papers into three distinct groups (in order of publication in this issue): six that focus on individual level consumer information processing and behavior, one that focuses on methodology, and four that focus on consumer–firm (or brand) relationships. This table also provides more specific information for each paper, including the type of review completed, the topical focus, and information relating to its empirical review scope. Seven of the papers conduct a meta-analysis of existing work, whereas the other four undertake a systematic (but non-meta-analytic) review.

Table 1 Papers in this issue: descriptives
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Individual level consumer information processing and behavior generalizations

Using an interdisciplinary meta-analytic approach, Ikonen et al. (2020) investigate how front-of-package (FOP) nutrition labels for food products affect various consumer perceptions and behaviors. In particular, they examine the impact of FOP information on consumers’ ability to identify healthier options and make more nutritional product choices. Offering implications for both managers and policy-makers, the authors observe that whereas FOP labels help consumers to identify healthier options, their influence on choice behavior is more limited. In addition, Ikonen et al. (2020) find that some information-labelling formats are more effective than others.

Iyer et al. (2020) examine a broad range of studies to identify, through meta-analysis, the key determinants of consumer impulse buying behavior, focusing on individual traits, personal motives, consumer resources, and marketing stimuli. Further, they propose an integrative framework that looks at the effects of both potential moderators (industry characteristics, methodological considerations) and mediators (self-control, mood) on these relationships, helping to resolve inconsistent results across published research. In particular, they find that the consumption context can substantially enhance or diminish the impacts of many of the studied determinants on impulse buying.

Although an understanding of consumers’ visual perception of products, places, and related objects is critical to effective marketing management and research, academic work that has been published to date on this topic has remained fragmented. In their systematic review, Sample et al. (2020) draw on relevant work from perceptual psychology, engineering, graphic arts, architecture, and marketing to develop a conceptual framework that they then use to organize the existing marketing-related literature. They examine five main components of visual perception: illuminance, shape, surface color, materiality, and location to help reveal key insights and identify promising next steps.

The paper by Rosario et al. (2020) undertakes a systemic review of existing work dealing with electronic word of mouth (eWOM) behavior by consumers. Using a motivation-opportunity-ability theoretical perspective, the authors conceptualize three distinct stages in the eWOM process: eWOM creation, eWOM exposure, and eWOM evaluation. Rosario et al. then use a dual lens approach (from the distinct perspectives of consumers and marketers) to synthesize existing research and propose a research agenda.

Drawing on established work in behavioral economics, the systematic review paper by Dowling et al. (2020) identifies and organizes published empirical research describing behavioral biases (i.e., deviations from rational behavior) in marketing. The authors develop a conceptual framework that encompasses two critical dimensions – three classes of deviations (nonstandard preferences, nonstandard beliefs, and nonstandard decision making) described across four phases of consumer purchase decision making (need recognition, pre-purchase, purchase, and post-purchase). This results in the identification of both connections and differences across categories in both dimensions.

Kranzbühler et al. (2020) use meta-analysis to investigate the effects of ten discrete emotions on consumer judgements and behaviors. They find that analyzing discrete emotions leads to superior prediction versus models that only examine core affect (valence and arousal). Further, they confirm that positive emotions consistently have stronger effects than negative emotions, and that gratitude has the strongest impact. Finally, Kranzbühler et al. observe that situational characteristics can actively moderate the sizes of these effects.

Methodological generalizations

Pricing researchers have often wrestled with how to best assess consumers’ willingness to pay (WTP) for consumer goods. Conventional wisdom has suggested that indirect methods measure WTP more accurately than direct methods. However, based on a meta-analysis of 77 published studies, Schmidt and Bijmolt (2020) find that indirect methods actually overestimate consumers’ real willingness to pay more than do direct methods. Further, they estimate the average bias across methods to be 21%, and observe that the size of the bias is greater for higher valued products, specialty goods, and within-subjects experimental designs.

Consumer–firm/brand relationship generalizations

Khamitov et al. (2020) systematically review 236 published articles dealing with brand transgressions, service failure and recovery, and product-harm crises. All three phenomena represent firm marketing failures as viewed by consumers. Despite core similarities, however, these three streams of research have developed independently of one another. Khamitov et al. propose a conceptual framework that synthesizes the streams, advancing a unified perspective that enfolds all negative firm events in marketing. In doing so, the authors identify and explicate seven overarching insights across three major themes (theory, dynamic aspects, and method), and reveal gaps that exist in the interfaces between the three streams.

The relationship between customer satisfaction and firm performance has been well-studied by academic researchers, yet contradictory findings have emerged. To provide greater clarity and improved managerial understanding of this important relationship, Otto et al. (2020) use a meta-analysis to examine 96 published studies of the effect. They find a significant and positive overall relationship, but also investigate various moderators as well as important antecedents to customer satisfaction. In particular, they find that marketing strategy factors have a strong impact on customer satisfaction, and that both how satisfaction is measured and the study context play important moderating roles.

Whereas recent reviews have provided clear insights regarding the benefits of relationship marketing for firms, researchers have paid far less attention to customers’ relational benefits. In their meta-analytic review of published relationship marketing studies, Gremler et al. (2020) investigate how three facets of customer relational benefits (confidence, social, and special treatment) are linked to relationship quality and switching costs, and how these two constructs are in turn connected to firm sales performance through the mediating effect of customer loyalty. They find that all three relational benefits matter, although confidence and social benefits have the strongest effects.

Finally, Auer and Papies (2020) examine cross-price elasticities using a meta-analysis of 115 studies. Although reviews from past decades have investigated this topic, major recent changes in the marketing landscape (e.g., the rise of online distribution channels, growth in private labels) call for an updated assessment of cross-price elasticity effects. Based on their analyses, Auer & Papies identify six main empirical generalizations. For example, they find that cross-price elasticities have decreased over time, high-stockpiling groceries have the highest elasticities, and long-term cross-price elasticities are larger than short-term elasticities.

Key contributions and primary focus

Returning to the set of potential contributions that review papers can make (as presented earlier), we have organized the selected papers in Table 2 to show both the primary nature of each paper and what we see as its key contributions. Seven of the papers are primarily domain-focused (Ikonen et al., Iyer et al., Kranzbühler et al., Khamitov et al., Otto et al., Gremler et al., and Auer & Papies), three are theory-focused (Sample et al., Rosario et al., and Dowling et al.), and one is methodologically-focused (Schmidt & Bijmolt). Below, we discuss the key types of contributions shown in the table (often focusing on exemplars rather than attempting an exhaustive discussion).

Table 2 Key contributions and primary focus, by paper
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Resolve definitional ambiguities; outline scope of topic

All eleven papers do a nice job of outlining the scope of their reviews. However, Khamitov et al. go further in their reconciliation of three related (but distinct) domain-focused streams of research. An essential part of their review involves clarifying phenomena that have been discussed in separately evolving research streams, requiring a very clear articulation of the review’s scope. Similarly, definitional clarity is an important element of all eleven reviews, but resolution of definitional ambiguities is critical for the three theory-focused papers. For example, the paper by Rosario et al. reviews very diverse definitions of eWOM and definitively resolves this confusion by proposing precise and useful definitions for three related eWOM components.

Provide integrated, synthesized overview

Five of the domain-focused papers (as well as Dowling et al.) offer integrated, synthesized overviews that are drawn from the authors’ careful reviews of published research. These overviews help organize the existing literature in a meaningful way to facilitate the identification of important moderators, mediators, antecedents, and consequences that relate to a focal phenomenon. The key here is that the elements enfolded into the overview already exist in the published literature, but are organized by the review paper in a novel and compelling manner. For example, Dowling et al. offer a unique organizing perspective (by type of deviation and by stage in the consumer purchase decision-making process) in looking at behavioral biases in marketing.

Reconcile inconsistencies

In general, the papers using meta-analytic techniques are able to convincingly identify the roles played by various potential moderators and mediators, and thereby reconcile different empirical findings found across existing studies. For example, not only do Kranzbühler et al. confirm that positive emotions consistently have stronger effects than negative emotions, they also provide a more nuanced view of how situational characteristics can moderate the impact of various specific emotions on important consumer outcomes.

Evaluate existing methods

Four of the papers in this special issue explicitly evaluate existing methods. First, Kransbuhler et al. compare the impact of combining emotions of the same valence (e.g., sadness, anger) versus the impact of studying discrete, individual emotions on consumer outcomes. Second, Auer and Papies investigate different approaches to estimating cross-price elasticities. Third, Ikonen et al. review the effectiveness of different publicly available labelling formats. Finally, Schmidt and Bijmolt examine (in detail) distinct ways of measuring consumers’ willingness to pay, looking at both direct and indirect methods. In all four papers, these critical assessments of existing methodological approaches result in clear recommendations for future practice.

Develop conceptual frameworks

In contrast to the synthesis of existing research described above, review papers strong on this dimension go beyond simply reorganizing existing findings in a more compelling way to provide a conceptual framework that meaningfully extends past perspectives. For example, departing from a traditional view, Rosario et al. propose three distinct stages in the eWOM process: eWOM creation, eWOM exposure, and eWOM evaluation, and do so with consideration of both consumers’ and marketers’ roles. Khamitov et al. offer a conceptual framework (comprised of seven overarching insights) that organizes the brand transgressions, service failure and recovery, and product-harm crises literatures, providing a unified perspective encompassing a wide array of negative firm marketing events. Finally, Sample et al. develop a conceptual framework that is anchored on five main components of visual perception, and then use it to describe the role of visual elements in consumer marketing.

Research insights, gaps, and future directions

All eleven papers are listed as strong on this contributory dimension. As we noted earlier, in our opinion, the usefulness of the insights that are generated from a systematic review (coupled with the clear articulation of a future research agenda) is what separates highly cited review papers from others. Thus, throughout the review process we emphasized the importance of this element, and we have only accepted papers that successfully deliver it.

Conclusion

The papers in this special issue span a broad array of topics and approaches. Despite the lack of a specific topical focus, we believe that all eleven reviews offer important generalizations about phenomena of interest to marketing practitioners and scholars. The authors use a systematic approach to critically collect and review existing findings, and then synthesize this material in an effective way to provide the reader with a better understanding of the focal phenomenon. Further, all of the selected papers offer significant new insights that emerge from their authors’ careful scholarship, insights that cannot be gleaned from an individual or small group of studies. Finally, the papers in this special issue provide guidance to researchers interested in understanding a particular phenomenon by setting out clear agendas for future research.

As editors, we are thankful for the substantial effort and thought that the authors invested in completing their review papers. The result is a set of well-crafted, interesting, and important papers that we are proud to share with the marketing community. In addition, we want to acknowledge the substantial contributions made by reviewers of the papers considered for this special issue (see Appendix).