Abstract
The concept of the Base/Bottom of the pyramid (BoP), since its first use in the early 2000 s, has been used by researchers and practitioners alike. The past 16 years has witnessed a significant increase in output of published research on the subject. This study aims to analyze the main contributions in this field, using a bibliometric approach. It considers key bibliometric indicators, such as leading authors, journals, institutions, sources, countries, and the most common keywords. A graphical visualization in bibliometric maps has also been developed, using the VOSviewer software. As expected, the results indicate a sharp increase in BoP research over the last 5 years. The most influential research is from the USA, although there has been a considerable wave of production from the global south. The results may be of interest for those hoping to gain an overview of the current state of BoP research.
Introduction
The concept referred to as base/bottom of the pyramid (BoP) was first used in the early 2000 s, by Coimbatore K. Prahalad and Stuart Hart [36], in their seminal work on T he Fortune at the Bottom of the Pyramid. This publication drew attention to the markets constituted by those living in extreme or relative poverty, who make up about two-thirds of the human population of the planet [6, 14]. There is no unified consensus in the literature whether the word base or bottom is suitable in BoP, and both terms are used to refer to Prahalad and Hart’s concept [36], so the acronym BoP is used here to refer to both, or either.
Hart and his colleagues at the BoP Global Network acknowledge three main stages of evolution in BoP discourse to the present time [7]. BoP 1.0, hitherto the dominant view, emerged from the core idea of an existing fortune or latent market at the bottom of the economic pyramid, to be exploited by businesses, emphasizing its commercial potential and depicting the low-income population solely as consumers [15, 36]. BoP 2.0 places its emphasis on the need for co-creation, and it has moved beyond the focus on selling to the poor. A wider set of roles are on offer in this view for the participation of low-income populations throughout the value chain, framing their potential contribution as extending beyond their capacity to consume, including also their potential as employees, suppliers, distributors, or partners [30]. BoP 3.0, as proposed by Casado Cañeque and Hart [7], responds to additional opportunities, complexities, and challenges in the practice of BoP business, including moves toward open-innovation ecosystems, last-mile distribution, and cross-sector partnership networks.
Over the course of this conceptual evolution, the study of BoP has attracted considerable attention, and hundreds of publications, conferences, and business summits have addressed the issue, from academic, policy, and practitioner stances [12]. The literature on BoP has evolved in quantity, quality, and complexity, and it exhibits wide spectrum of representation, contextualization, interpretation, and implementation of BoP [19]. Research on BoP issues has been conducted on a wide range of subjects, including the analysis of innovation schemes for BoP markets [13, 22], public policy considerations for BoP [44], and use of BoP business ventures in development cooperation for the financial sustainability of aid flows [31].
This growing stream of research on the concept indicates that a bibliographic analysis of the main contributions to this field is worth a review. Thus, this study develops a bibliometric analysis of BoP research, using the core collection of the Web of Science.
Bibliometrics quantitatively studies bibliographic material [3]. From a quantitative analysis of published sources, a bibliometric analysis can enable an evaluation of the impact or performance of published research through the use of bibliometric indicators, including the h-index, journal impact factor, and other normalized indicators of citation impact [29].
The academic literature provides a variety of examples of bibliometric studies in the social sciences, including the subdisciplines of management [32], psychology [40], innovation [5], entrepreneurship [21], social entrepreneurship [37], creativity in business economics [8], international business [10], sustainability in business education [9], business incubators [1], arts-based management [11], information technology [2], organizational failure [20], economics [28], and marketing [25].
The remainder of this document continues as follows. Section 2 describes the methodology used in this study. Section 3 presents and analyses its results for the bibliometric indicators under study, and it also gives a graphic visualization of the bibliometric data. Finally, Section 4 provides the conclusions of this study.
Methodology
This study used a bibliometric approach to information obtained from the Web of Science (WoS) core collection, maintained by Clarivate Analytics. Although other academic databases exist, such as Scopus and Google Scholar, WoS is widely regarded as the main database to use for a comprehensive and accurate exploration of the academic literature. In March 2018, the WoS core collection was reported to have more than 20,000 journals and 1.4 billion cited references in its archives. It is generally believed that the contents of the WoS core collection meet the highest quality standards in academic research.
It is important to note that the materials for this study are drawn from those available on WoS in March 2018, so the results can only be a reflection of the particular state of the field at the specific point in time. Because this database is continually evolving as newer publications arrive and the associated growth in citations, the findings reported here may differ from others obtained at other times.
This study uses the search operator OR in the topic terms to include all papers in WoS core collection that contained any of the following keywords associated with BoP studies: base of the pyramid, bottom of the pyramid, base of pyramid, bottom of pyramid, base of the economic pyramid, bottom of the economic pyramid, base of the income pyramid, bottom of the income pyramid, BoP business*, BoP market*, BoP communit*, and BoP population*. This initial query produced 579 publications. This group was reduced by being limited to articles and reviews only, resulting in 405 papers.
The specificity of the sample was increased by adding two additional filters. First, the query was limited to documents published between 2002 and 2018 because this was the time period most relevant to this study. Next, using WoS research areas, the results were filtered to exclude subtopics that, although matching a keyword, have no relation to BoP research. Chemistry, crystallography, emergency medicine, family studies, materials science, physics, religion, spectroscopy, and surgery were excluded. These two filters reduced the output to 336 results. Finally, the sample was screened for inaccuracies, identifying and excluding 10 results that were not related to BoP research. The final sample included 326 papers (Fig. 1). The number of publications in BoP research in WoS shows a sharp growth trend, with the most significant increase in the number of published papers beginning in 2012, implying that interest in BoP is growing.
Publications on BoP per year.
This study used several bibliometric indicators, including the total number of papers, total citations, and h-index. The h-index was proposed by Hirsch [16] to quantify an individual’s scientific output by integrating the number of published papers and the number of citations into a single measurement.
Additional indicators were used to determine the productivity and influence of authors, institutions, countries, and journals. The number of articles equal to or above a citation threshold [26] is used to determine the quantity of papers that reach a specific level of influence. The ratio of total citations per study measures the impact of each paper [27].
A graphic visualization of the results in bibliometric maps is created using VOSviewer software, developed by a research group at Leiden University [42]. Three types of connections were considered: co-occurrence of keywords, co-citation, and bibliographic coupling [41]. Keyword co-occurrence networks showed the most common author keywords appearing in a field [5]. Co-citation is where two publications are cited together by a third [39]. Bibliographic coupling, on the other hand, occurs when two publications both cite a third [18]. Bibliographic coupling shows overlap in reference lists, and a greater degree of it implies a larger number of shared references between two publications [43].
The number of citations of one study can be used to gage the importance and influence of a publication. Table 1 presents the general citation structure found in BoP research, as judged by the information obtained from WoS. Analytical purposes dictated five citation thresholds. The results showed that only eight papers (2.45%) of those isolated received 100 or more citations; 8.90% received 50 or more cites, and 21.78% were cited 20 or more times. More than 110 studies received 10 or more citations, and almost 77% of the papers in the sample had been cited at least once since the publication.
General citation structure of BoP research in WoS
General citation structure of BoP research in WoS
Notes: ≥100, ≥50, ≥20, ≥10, ≥1 = number of papers with equal or more than 100, 50, 20, 10, and 1 citations, respectively.
Ted London and Stuart L. Hart [24] had the most cited paper in the sample, with 460 citations found in WoS. Their work discussed the strategies used by multinational corporations (MNCs) to reach the markets at the base of the economic pyramid. This was followed closely by a work titled Serving the World’s Poor, Profitably, published in Harvard Business Review by Prahalad and Hammond in 2002 [35]. Then, with 246 citations in WoS, the work of Karnani [17], which presents an argument opposing the mirage of business in markets at the base of the pyramid, is the third most influential paper in BoP studies.
Other influential studies found in the results that have 100 or more citations were studies by Hart and Christensen [15]; Seelos and Mair [38]; London, Anupindi, and Sheth [23]; and Webb, Kistruck, Ireland, and Ketchen, Jr. [45]. An examination of citations per year indicated that Prahalad [34] and Kolk, Rivera-Santos, and Rufín [19] each had a longer-term and significant impact. Prahalad’s work had 13.14 citations per year, and Kolk, Rivera-Sangos, and Ruffin received 12.6 annual cites for their article. It should be noted that these results only accounted for papers that were published in scientific journals counted in the core collection of WoS. Table 2 presents the 30 most cited studies.
The 30 most cited studies according to WoS
The 30 most cited studies according to WoS
Notes: R = rank; C/Y=citations per year; TC = total citations.
The co-citation connections in BoP publications were generated using VOSviewer software. Table 3 lists the 22 most cited documents, of which 6 are books and 16 are articles. The most influential book published in this area was that of Prahalad [33], published by Wharton School Publishing. One of the other most influential documents is the seminal work of Prahalad and Hart [36], published in the business journal Strategy+Business, which is not recognized as a source of research by databases like WoS.
The 22 most cited documents in BoP research
Notes: A = Article; B = Book; TLS = Total Link Strength.
It was also of interest to examine the most productive and influential authors. Productivity was measured by the number of publications by each author, and the measure of influence takes into account the number of citations received by the total production of each author. Table 4 presents the 25 most productive and influential authors, as judged by information in the WoS. Thus, the three most influential authors in BoP studies were Stuart Hart, Ted London, and Coimbatore K. Prahalad. Prahalad had the highest ratio (total citations/total studies), with an average of 265.50 cites per publication. Hart was the most cited author in total, with almost 700 total citations reported in WoS. Then, Madhubalan Viswanathan had the largest number of studies in the BoP field, with ten publications appearing in the WoS database. The topics addressed in his authored and co-authored publications included marketing management and decision making in subsistence markets. Viswanathan’s work had an h-index of seven, indicating that seven of his papers have been cited at least seven times. Kistruck, Singh, Karnani, and London were also among the authors with the highest productivity.
The 25 most productive and influential authors
The 25 most productive and influential authors
Notes: R = rank; TS = total studies; TC = total citations; H = h-index; TC/TS=citations per study; ≥100, ≥50, ≥20, ≥10 = number of papers with equal or more than 100, 50, 20, and 10 citations.
The graphic visualization of author co-citation networks by the VOSviewer (Fig. 2) shows Prahalad’s prominence in BoP research. Hart, London, Karnani, and Viswanathan also appeared as notable nodes, implying a greater number of citations and co-citations.
Co-citation of Authors.
Table 5 lists the 20 most influential journals in BoP research. Harvard Business Review (HBR) was the most influential journal in this subject area, with a total of 585 citations in WoS for its seven publications in the subject. This gave a ratio of 83.57 average citations per study. An article by Prahalad and Hammond [35] had the greatest influence of all HBR publications, surpassing the threshold of 100 or more citations. The Journal of International Business Studies (JIBS), California Management Review (CMR), and the Journal of Business Research (JBR) were also among the most influential journals. JBR had the greatest h-index, with 11 papers having been cited at least 11 times. With a total of 17 articles published on the subject, the Journal of Business Ethics (JBE) had the largest number of publications of BoP studies. JBE papers were cited 187 times, with eight receiving at least eight citations. VOSviewer software allows the influence of particular sources to be perceived in more detail. Figure 3 shows a bibliometric map of the existing co-citation connections of sources that have published BoP research. The map has a threshold of 20 citations and shows the 100 most representative co-citation network connections.
The 20 most influential journals in BoP research
The 20 most influential journals in BoP research
Notes: R = rank; TS = total studies; TC = total citations; H = h-index; TC/TS=citations per study; ≥100, ≥50, ≥20, ≥10 = number of papers with equal or more than 100, 50, 20, and 10 citations.
Co-citation of sources.
HBR displayed one of the widest networks, reflecting again the influence of its publication. The Academy of Management Review and JBE also appeared with their broad co-citation networks. The book The Fortune at the Bottom of the Pyramid [33] was also another commonly cited source. This graphical visualization was supported by the data shown in Table 6, which lists the 20 most cited sources according to the total numbers of citations and co-citation links.
The 20 most cited sources
Notes: R = rank; Cit = Total citations; CLS = Co-citation links.
Another interesting aspect considered was the geographical and institutional distribution of BoP research. This was assessed by analyzing the universities and countries that had greater representation in BoP publications in WoS. The 30 most productive and influential institutions are presented in Table 7 and Table 8 lists the leading 25 countries in the world. Universities from the USA were dominant in their influence, accounting for the top 10 institutions in the ranking in terms of total citations. The University of Michigan was the most influential, with more than 1000 citations of its 15 papers on BoP. Its h-index was 10, meaning that 10 of its papers received 10 or more citations.
The 30 most productive and influential institutions
The 30 most productive and influential institutions
Notes: R = rank; TS = total studies; TC = total citations; H = h-index; TC/TS = citations per study; ≥100, ≥50, ≥20, ≥10 = number of papers with equal or more than 100, 50, 20, and 10 citations.
The University of Michigan was also the most productive institution, as judged by the number of publications, followed by the University of Illinois Urbana-Champaign, which published 10 articles on BoP.
In addition to institutions representing such commonly leading countries, such as the UK (3), Canada (3), and the Netherlands (1), universities from emerging countries in the global south, such as India (1) and Mexico (1), also appeared. This trend may indicate the relevance of BoP issues for low-income and middle-income countries. A similar trend could be seen in the aggregate distribution of the 25 most productive and influential countries (Table 8). The list was led by North American and Western European countries. The USA was the top producer and has the most influence, with 129 total publications cited 3416 times in WoS. This was followed by the UK, Canada, Germany, and the Netherlands, completing the top five positions. Measured by ratio of total citations per study, Norway was the most notable country, with an average of 45.5 citations per publication. India was the leading emerging country in the ranking, with 233 citations and 43 documents published about BoP, reaching an h-index of seven.
The 25 most productive countries in BoP research
Notes: R = rank; TS = total studies; TC = total citations; H = h-index; TC/TS = citations per study; ≥100, ≥50, ≥20, ≥10 = number of papers with equal or more than 100, 50, 20, and 10 citations.
Using bibliometric maps, the co-citation and bibliographic coupling of institutions and countries could be further analyzed. Figure 4 presents the institutions with the greatest degree of bibliographic coupling, with a threshold of two papers and the 100 most influential connections. The map provides a graphic visualization of existing connections among institutions, based on the affiliation of the authors publishing BoP research. In addition, Fig. 5 displays the bibliographic coupling for countries, with a threshold of two papers and the 50 most significant connections. The USA appeared as clearly the most relevant node on the map. Note also that as can be seen, taking the data shown in Table 8, the graphic displays two most significant networks for BoP research, namely, that of the traditional developed countries and the emerging and developing countries.
Bibliographic coupling of institutions.
Bibliographic coupling of countries.
The main co-citation linkages between institutions are shown in Fig. 6. The map was built with a threshold of two papers and 100 most relevant connections. A high degree of co-citation among North American institutions was evident, with a greater dispersion among the European universities shown.
Co-citations by institution.
Lastly, this study analyzed keyword co-occurrences to identify the most common terms used by BoP authors to describe their work. VOSviewer software was used to develop a keyword co-occurrence map (Fig. 7) that shows the 100 most significant connections, with a threshold of two co-occurrences per keyword. Base of the pyramid was the most common keyword used in BoP research, followed by Bottom of the pyramid. Minor variations in the keywords (e.g., with or without the accompanying acronyms) were used to illustrate the different ways in which the most commonly used keywords appear in publications in the field.
Co-occurrence of keywords.
This study provided a bibliometric analysis of the current state of research in the study of BoP. The WoS core collection was used, with information reported in the database as of March 2018. The lack of international agreement on a single bibliometric measure was acknowledged in this study, leading to a range of indicators being used to increase the informative breadth. The reported measurements included the total number of papers and citations, h-index, and ratios, such as citation thresholds and average citations per study. This study analyzed these key bibliometric indicators to determine the productivity and influence of the leading authors, journals, institutions, and countries in the field. To complement and deepen the analysis, VOSviewer software is also used to create bibliometric maps. Three types of connections were examined, namely, bibliographic coupling, co-citation, and co-occurrence of keywords.
The results showed that Hart, London, and Prahalad were the three most influential authors in BoP research. Karnani, which is among the most productive and influential authors, also appeared as the most prominent opposition voice. HBR, JIBS, CMR, JBR, and MIT Sloan Management Review were the most cited journals in this field. Some non-journal sources, such as books and a non-scholarly periodical, were also within the most influential publications in BoP research. The most significant of these was the seminal book by Prahalad, first published in 2004, The Fortune at the Bottom of the Pyramid. This study also found the most productive and influential institutions and countries. North American and Western European countries were in the lead here, with the USA as the most productive and influential country in BoP research, followed by other traditional leading countries, such as the UK, Canada, and the Netherlands. However, the influence of emerging countries of the global south should not be passed over, and the ranking included India, South Africa, Mexico, and Colombia.
The information and analyses provided in this study may be found useful by a readership that has an interest in gaining an overview of the current state of BoP research. This could be for academic purposes or practical policy. The authors acknowledge that the results presented here were limited by the specific methodology implemented. Furthermore, because the WoS database exhibits constant change, the data reported might shift over time, and the figures and data presented are only valid for the timespan specifically under study. In addition, it must be noted that other important authors and publications in the BoP field are not included in the WoS core collection and thus evaded the scope of this study.