Romano and Ratnatunga (1996) and Ratnatunga and Romano (1997) brought bibliometrics into the world of entrepreneurship studies towards the end of the 1990s with their works focused on small businesses. However, the first bibliometric analysis dealing with entrepreneurship as a discipline was carried out by Dery and Toulouse (1996) in order to shed light on its social structure. Ever since those first seminal bibliometric research projects on entrepreneurship, there have repeatedly been works dealing with the discipline as a whole, culminating in a special issue published in 2006 by one of the most prestigious journals in the field (Gartner et al. 2006).

All of those studies, and some of the more recent ones (Ferreira et al. 2019; Xu et al. 2018; Landstrom and Harirchi 2018), have contributed fundamentally to the creation of a certain order in an apparently chaotic and contradictory literature with disparate meanings, views, and ways in which entrepreneurship is used and referred (Audretsch et al. 2015), examined how the discipline has evolved, given an overall view of the structure of the field, observed its social networks, spotted tendencies, discovered knowledge gaps and helped plan future lines of research. However, despite being a special, and particularly difficult, type of research that brings together two fields (bibliometrics and entrepreneurship) with peculiar characteristics, and approaches a discipline in its totality, little is known still about it. No review has yet taken up the task of analysing the works that are the result of this kind of research. The study presented below attempts to bridge that gap and is designed as a study of studies, offering a double perspective, looking at the contributions made to entrepreneurship as well as presenting a vision from a point of view of bibliometrics.

The aim of this article is to explore the different bibliometric analyses carried out on entrepreneurship as a discipline by putting together a representative sample selection of documents and subjecting them to a subsequent analysis. In terms of methodology, it employs an adaption of the Systematic Literature Review (SLR) developed by Tranfield et al. (2003) and a content analysis using text mining software in order to detect key features and to respond to the following research questions: How have studies of this type evolved? Have they been able to offer a picture that faithfully reflects the discipline? What have their main objectives and conclusions been? Which specific problems were they confronted with? Have researchers been applying the latest tendencies in bibliometrics? What has bibliometrics been able to contribute to the research in entrepreneurship so far, and what can it still contribute in the future? What is the future for this kind of research?

The rest of the study is divided into five sections. The starting point is a literature review that looks mainly at the origins, evolution, fundamentals, tendencies and limitations of bibliometrics. The next section deals with bibliometric research in entrepreneurship. The third is centred around the most significant methodological considerations. The fourth shows a discussion of the main results obtained. The final section is a presentation of the main conclusions.

Entrepreneurship is an extraordinary phenomenon. It is a field that is able to bring together the interests of institutions, scientists and society as a whole. It is so special that there is almost unanimous agreement on its significance. This has led to a situation in the last decades where the number of institutions that offer their support to new entrepreneurs has not stopped growing, and a document corpus has evolved, which aims to decipher its key characteristics. The question remains, however: Is it a phenomenon, a field or a discipline?

Despite its undeniable social recognition and ‘popularity’, a series of questions have always provoked a profound debate about it in academic circles, as shown in Kushkowski (2012). The debate includes questions related to the way in which research is conducted (Venkataraman 1997), to methodology (Busenitz et al. 2003; Low and Macmillan 1988), or to the fierce debate over whether it is an independent and legitimate discipline (Shane and Venkataraman 2000) or an interdisciplinary field based on the study of empirical phenomena (Sorenson and Stuart 2008), and even those tackling its essence, the actual definition of entrepreneur (Carlsson et al. 2013), and the lack of consensus hereon.

This definition remains elusive, heterogeneous and complex like each of the entrepreneurs it represents. On the political-institutional level there is an elevated consensus traditionally based on the important economic and social benefits entrepreneurship generates, which has almost without exception been the main reason for its study (van Praag and Versloot 2007). These widely studied benefits can be translated into more and greater economic growth, increasing productivity and competitiveness, the discovery of opportunities, emergence of innovation and dynamic generation of employment (Shane and Venkataraman 2000; Audretsch and Thurik 2001; Audretsch et al. 2006; Acs et al. 2009).

Characterised by an apparently chaotic and contradictory literature (Audretsch et al. 2015), it positions itself as an ideal candidate to take advantage of the potential of bibliometrics. Zupic and Cater (2015) point out that in the context of management and organisation, bibliometric methods contribute, among other effects, to the synthesis of past research findings, to the advancement and discovery of new lines of investigation, to the introduction of systematic, transparent and reproducible review processes, to the improvement of the quality of reviews, to the mapping of different specialties, to the introduction of objective measures for literature evaluation leading to increased rigor and reduced bias, and to the detection of formal as well as informal networks (invisible colleges). These tools when applied to entrepreneurship multiply its possibilities. Their use allows researchers the opportunity to make headway in their theoretical understanding of it and to analyse such relevant questions as the ones mentioned, in greater depth. Research in this area is still young and its representation is weakened as it blurs into other categories in the two main scientific reference bases (Web of Science and Scopus).

The generalised use of databases such as Web of Science (WoS), Scopus and others as a crucial resource which allows scientists to access an elevated number of documents and all the bibliometric information they index (references, citations, etc.) in their research area, as well as the development of software that provides better handling of the resulting data and makes the tasks involved in their analysis more efficient, has led to a more widespread use of bibliometric tools: Sitkis (Schildt 2002), one of the first; Bibexcel in combination with Pajek (Persson et al. 2009), and others such as SciMAT, HistCite, CiteSpace, VOSviewer.

The documents that contain the knowledge accumulated in entrepreneurship are scattered over a variety of, at times very different, categories in the two mentioned databases. As Landstrom et al. (2012) indicate, the phenomenon is multidisciplinary in nature, and registers mainly under Management, Business, Economics (WoS) or Business Management and Accounting, Economics, Econometrics and Finance (Scopus), as well as in other categories like Psychology, Sociology, History, etc., but to a lesser degree.

An adaption of the procedures developed by Tranfield et al. (2003) has been followed. Systematic literature reviews (SLR) differ from traditional ones in that the process is reported openly in the same way empirical research would be, and that they are governed by transparency, clarity, equality and accessibility (Pittaway and Cope 2007). The methodology, applied and developed in detail in the context of Management and Social Sciences in works such as Liñan and Fayolle (2015), Pittaway et al. (2004), Thorpe et al. (2006), has been modified to adapt itself to the objectives and requirements of this study. The procedure which has been followed is illustrated in the Figure 1.

Step 1 Search Start: The objective of the review is to respond to different research questions: How has bibliometric research on entrepreneurship as a discipline been conducted? What have been the main objectives and conclusions? What specific challenges had to be faced and how were they overcome? Has a reliable image of the field emerged? Are the results up to date? What can bibliometrics offer to research into entrepreneurship and what has it contributed so far? Have advances in bibliometrics been used to keep research up to date? What does the future of this type of research look like?

In order to comply with such a variety of objectives, a non-restrictive strategy has been opted for, performing the document search in the two reference databases of the scientific community, WoS and Scopus, and using Google Scholar as an auxiliary tool to find more documents and download those whose access is restricted in the former.

In terms of the formula applied in the search, after testing different combinations and performing a number of tests runs it was decided to carry out accumulative searches for word pairs without applying any type of filters such as year or document type. Keywords associated with bibliometrics detected in previous works on information sciences were used (Chang et al. 2015), in total 23 terms and their possible lexical variations of occurrence were collected (for example: co-citation analysis / cocitation analyses), combined with the root “entrepr *”, strategy previously used in bibliometric analysis on entrepreneurship (Cornelius et al. 2006, Schildt et al. 2006). A combination of terms that could include the different bibliometric works were used for document selection. The complete sequence is detailed as supplementary material in Annex 1.

Following this strategy, 260 documents were compiled from WoS and 257 from Scopus. The inclusion/exclusion criteria were established in accordance with the previously mentioned objectives

Step 2 Search Start: All titles and abstracts of every document compiled according to the previously described criteria were read. Applying the first filter, the result already provides valuable information for the study. Among those documents discarded for their lack of global focus on entrepreneurship, an increasing amount of literature can be found where bibliometric analyses are used as a main tool or as a complement to explore specific lines or sub-fields of research that are closely linked with entrepreneurship (family business, female entrepreneurship, social entrepreneurship, born global firms, informal entrepreneurship, international entrepreneurship), or simply to answer very specific questions in certain lines of investigation (Caputo et al. 2018; Galvao et al. 2018).

The result was a first list of 30 documents:

The wide search sequence produces documents that do not tie in with the proposed objectives. It does, however, offer more results to process and picks up some as Yu and Tang (2014) or Qian (2014) that would not have been included otherwise. Furthermore, the results are enriched by allowing any type of document to be included. Auxiliary searches were carried out in Google Scholar, using the same strategy, which resulted in 6 additional documents that had previously not been detected in Scopus or WoS.

This section and the next one will inevitably introduce a certain level of subjectivity, as the inclusion or exclusion, for example, of those documents which generate doubts, such as Bhupatiraju et al. (2012) or Schmitz et al. (2017), was decided in accordance with the objectives of this review, although it is subject to different interpretations. In the end, the mentioned documents were not included.

Step 3 Characterization: In the third phase, the definitive sample emerged. To achieve this, all documents produced in the previous phase were read, discarding those where access has been impossible (some documents in the sample are proceedings that weren’t available in their complete form). Additionally, conference presentations were substituted by the articles that later reported on them.

The list contains two works that compiled a list of bibliometric studies in entrepreneurship as part of their research: Landstrom and Persson (2010) and Teixeira and Ferreira (2013). They were used in order to be contrasted with the results obtained and to add documents that had not been found but which comply with the criteria for the review. The final result consisted of 40 documents1, subsequently, the sample was characterised, and all the relevant information required to respond to the proposed research questions was identified.

Step 4 Content Analysis: Text mining software was used to detect key characteristics and to increase the objectivity of the study. The process followed mainly consisted of:

This phase and the next one (step 5: conclusions) are developed together with the results and conclusions of the article.

The analysis of the objectives of the 40 studies of the sample was carried out after the individual reading of each document. The objectives were isolated in an individual text document for each element of the sample and the 40 resulting files were introduced in the text mining software. According to the WordStat User Guide, the Topic Extraction function attempts to uncover the hidden thematic structure of a text collection through natural language processing and statistical analysis. This function is used to increase objectivity and facilitate interpretation of content.

The objectives of the articles are usually found in the introduction section. The number of words that shape the text of the objectives is usually reduced; therefore, it was decided to extract only the 7 most representative thematic nuclei at the level of lexical coherence and statistical figures, as shown in Figure 4.

The thematic study of the items obtained showed a high thematic coherence, this metric is based on measures of how frequently individual words occur and pairs of distinct words co-occur (Kuhn, 2018). Values close to 0 indicate optimal figures and consequently increase cohesion in the topics (Mimno et al. 2011). Table III shows the 7 topics detected. WordStat uses an algorithm to automatically assign a label to each group, as well as the main keywords associated with that topic in descending order according to the cut-off criteria (in this case, minimum frequency, 4); the total frequency of the main keywords of the thematic core, the number of cases or documents that contain at least one of the keywords and their percentage.

As can be seen, the thematic core Field of Entrepreneurship, how could it be otherwise, is the most prominent, has a coherence of 0.388; a total frequency of 98; appears in the objectives of 39 of the 40 documents, that is, in 97.5% of cases. The rest of the thematic cores also show very positive values, for example Based Citation, Entrepreneurship Research and Evolution Studies. It is noteworthy that two particular thematic nuclei, Region Similarities and Convergence Cohesion, are appearing in 10 and 6 documents respectively.

The analysis of the main motivations for carrying out this type of research by looking at proposed objectives reveals that 1996 was the year when the first global work (Dery and Toulouse 1996) of this type was elaborated to “reveal the social structuration of knowledge in entrepreneurship”. The objectives have changed over time and show unique characteristics that are not typical of bibliometric research in general; e.g. namely to prove the legitimacy of the discipline. Observing the frequency with which authors employ words, and the topical groupings by means of factor analyses carried out using text mining software, a group of significant documents appears which are based on a solid theoretical foundation and recur to bibliometrics in order to expose cohesive and converging features in the discipline (Busenitz et al. 2003; Campos et al. 2012; Cornelius et al. 2006; Gregoire et al. 2006; Reader and Watkins 2006; Schildt et al. 2006).

The rest of the topic groups that emerge are more common and tie in with the need described by Low and Macmillan (1988), “a body of literature develops, it is useful to stop occasionally, take inventory of the work that has been done, and identify new directions and challenges for the future”. They use bibliometrics to compile the most fundamental works and authors, and to show their evolution as well as their social structure to improve understanding of them, and to make advances in their theoretical construct.

The procedure followed with the limitations and conclusions is similar to that described in the previous section. Only the thematic nuclei have been extended to 8, since the texts that include them are usually more extensive at the end of the documents. The analysis of the conclusions of the sample documents shows different topic groups: Category Management, Program top, Significant article, Concepts Strong, Appears Identified, Innovation Related, Entrepreneurship Research and Core Themes (Figure 5).

Table IV shows the main statistics related to the conclusions and the main thematic associations. Three of them appear in a greater number of documents:

“Appears Identified”: It is linked to obtaining and identifying main trends within the field of entrepreneurship, presents high frequencies of the keywords contained, appears in 36 documents and shows high cohesion.

“Entrepreneurship Research”: It is a group related to the objectives of the documents, it also appears in 36 articles and keywords emerge related to the increasing disciplinary cohesion and converging nuclei.

“Category Management”: reflects the idea that most of the bibliometric research coincides in signalling that entrepreneurship is a discipline with a markedly multidisciplinary character whose essence lies in other main fields or categories (Management, Business and Economics). The words that configure it are present in 32 of the 40 documents in the sample with high frequency and cohesion.

The rest of thematic associations (program top, concepts strong, innovation related, core themes, significant article), although they decrease in the number of cases and frequency (even if they are high) deepen conclusions related to greater internal theoretical strength related to innovation and the emergence of nuclei of recognizable authors linked to the strong growth of the field of entrepreneurship.