Introduction

The main aim of this article is to assess the most-cited scholars in 20 criminology and criminal justice journals in 2015, and to compare them with the most-cited scholars in these journals in 1990–2010 and with the most-cited scholars in the Asian Journal of Criminology (AJC) in 2015. A previous article in this journal (Farrington et al. 2019) reviewed evidence that numbers of citations are a valid measure of scholarly influence. That article compared the most-cited scholars in AJC in 2006–2015 with the most-cited scholars in the Australian and New Zealand Journal of Criminology (ANZ), Criminology (CRIM), and the European Journal of Criminology (EJC) during the same time period. Generally, the most-cited scholars in AJC tended to be based in the United States, tended to be working in the area of developmental and life-course criminology, and tended to be highly cited in the other three journals. However, few Asian scholars were highly cited in the other three journals.

Another previous article in this journal (Iratzoqui et al. 2019) pointed out that long-term longitudinal studies of the most-cited scholars are extremely rare, and reviewed the advantages of this approach. That article documented the most-cited scholars in four international journals (ANZ, CRIM, British Journal of Criminology—BJC, and Canadian Journal of Criminology and Criminal Justice—CJC) in 2011–2015 and compared them with (a) the most-cited scholars in these four journals in 1986–1990, 1991–1995, 1996–2000, 2001–2005, and 2006–2010, and (b) the most-cited scholars in AJC in 2006–2010 and 2011–2015. Generally, the most-cited scholars in the four international journals tended to be highly cited in AJC, and their most-cited works tended to be on developmental and life-course criminology, theoretical issues, statistics, or policy issues.

It might be argued that the most-cited scholars in four or five international journals (even very prestigious ones) are not necessarily the most-cited scholars in criminology and criminal justice more broadly. In order to address this issue, Cohn et al. (1998) studied citations in 20 criminology and criminal justice journals (five American criminology, five American criminal justice, five international criminology, and five international criminal justice). Because of the large number of citations and the large amount of work involved, they studied citations in only one year—1990. This analysis was then repeated for 1995 (Cohn and Farrington 1999), 2000 (Cohn and Farrington 2008), 2005 (Cohn and Farrington 2012), and 2010 (Cohn et al. 2014). The present article extends this series up to 2015 and compares the most-cited scholars in these 20 journals in 2015 with the most-cited scholars in AJC in 2015.

The 20 journals, chosen from major journals that were being published in 1990, are as follows: five American criminology journals (CRIM, Journal of Quantitative Criminology—JQC, Journal of Research in Crime and Delinquency—JRCD, Journal of Interpersonal Violence—JIV, and Violence and Victims—VAV), five American criminal justice journals (Justice Quarterly—JQ, Journal of Criminal Justice—JCJ, Crime and Delinquency—CAD, Criminal Justice Review—CJR, and Federal Probation—FP), five international criminology journals (ANZ, BJC, CJC, Crime, Law, and Social Change—CLSC, and Criminologie—CRGE), and five international criminal justice journals (Crime and Justice—CAJ, Criminal Justice and Behavior—CJB, International Journal of Comparative and Applied Criminal Justice—IJCA, International Journal of Offender Therapy and Comparative Criminology—IJOT, and Social Justice—SJ).

The key questions are as follows:

  1. 1.

    To what extent are the most-cited scholars similar or different across 10 American journals, 10 international journals, and AJC?

  2. 2.

    To what extent are the most-cited scholars similar or different across 10 criminology journals, 10 criminal justice journals, and AJC?

  3. 3.

    To what extent are the most-cited scholars similar or different across time, from 1990 to 2015, in five American criminology, five American criminal justice, five international criminology, and five international criminal justice journals?

  4. 4.

    What are the most-cited works of the most-cited scholars?

Methods

Citation data primarily draw from one of three sources: 1) the Social Sciences Citation Index (SSCI); 2) online scientific archives such as Google Scholar and Elsevier’s Scopus, or 3) raw citation counts. Farrington et al. (2019) highlight the various reasons why the first two sources are less than ideal for citation analysis, including that they (1) may include self-citations; (2) may be unclear about what journals, databases, and time periods are covered, and how often the system is updated; (3) can produce variable results based on what search terms are entered; and 4) do not correct for errors in reference lists or missing authors (e.g. where the citation says “et al.”) in the original citation.

The third source, raw citation counts, yields much more valid results for citation analysis. Raw citation counts are derived from manual examinations of reference lists of academic publications, counting the number of citations of a given scholar, work, or journal. Cohn and Farrington have used this method throughout their international citation analysis research, beginning with their first work (Cohn and Farrington 1990), and in studies of citations in five-year time periods since then (i.e., for 1986–1990, 1991–1995, 1996–2000, 2001–2005, 2006–2010, and, most recently, 2011–2015). However, raw citation counts are not included without correction. As part of this method, the data are cleaned in order to eliminate self-citations; to correct names of scholars in terms of spelling and initials; to include complete author lists when “et al.” is used; and to explicitly specify what outlets are searched across what specified time periods.

Data for the current analyses were obtained from the reference lists of every article in all issues of each of the journals during the calendar year 2015. The classification of “article” included research notes, comments, and rejoinders, but excluded book reviews, book review articles, editorials, letters, and obituaries. Papers were also excluded if institutions were reported as authors. Citations were excluded if they were self-citations (e.g., if David P. Farrington cites an article written by David P. Farrington) but were included if they were co-authored citations (e.g., Ellen G. Cohn would be counted if David P. Farrington cites an article written by Ellen G. Cohn and David P. Farrington). Unpublished reports and conference papers were included if they were cited, but citations of institutional authors were not included.

In addition, the “nationality” of each scholar was coded and analyzed, based on the author’s institutional or organizational affiliation as listed in the publication, rather than their country of origin. Thus, for the purposes of the current analyses, “American” scholars were defined as those scholars based in American institutions.

Citations collected from reference lists were inputted into a file that generated counts for each cited author in each article of each issue of all the journals. The data were then cleaned in a multi-step process. References with multiple authors were duplicated so that each co-author could receive a count for the citation. Similarly, references that specified “et al.” rather than listing all authors were corrected to include all authors, when that information was available. References were also manually checked to ensure that no references were omitted, to correct any mistakes in reference lists, including misspelled names or incorrect or missing initials, and to merge scholars who had multiple names (e.g., David Farrington and David P. Farrington). Different orderings of names (e.g., Jianhong Liu and Liu Jianhong) were amalgamated, as were different names of the same person, where known (e.g., where names were changed after marriage or divorce). The final cleaned list of references of each journal was then sorted alphabetically and the number of times each name occurred was counted for a final total.

Results

Table 1 reports the total number of articles, authors, and eligible cited scholars in each category of five journals in 2015. Several trends may be observed. First, American journals tend to publish the most articles, with 516 articles published in the included American journal groupings for the year 2015, compared with 371 articles in the international journals. Second, American journals tended to primarily cite works by American scholars, particularly in criminal justice journals (90.3%). This is perhaps not surprising given the frequent difficulty in comparing criminal justice policies internationally. However, American scholars tend to dominate the field as a whole, representing a majority (57%) of cited scholars in 20 journals across the world.

Table 1 Articles, authors, and eligible cited scholars in 20 Journals in 2015
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The average number of articles published in international journals in 2015 was 37. In contrast, AJC published 18 articles in 2015. The average number of authors (not necessarily all different persons) in international journals was 91, compared with 48 in AJC. Of the authors in international journals, 33.6% were American, compared with 39.6% in AJC. The average number of cited scholars (again not necessarily all different persons) in international journals was 4212, compared with 1593 in AJC. The average number of cited scholars per article was 89 in AJC, compared with 114 in international journals.

Table 2 shows the five most-cited scholars in each journal in 2015. Among the American criminology journals, Robert J. Sampson dominated, being the top-cited scholar in three of the journals (CRIM, JQC, and JRCD), with Murray A. Straus being the top scholar in the other two journals (JIV and VAV). Sampson was also the most-cited scholar in two of the American criminal justice journals (JQ and CAD), as well as one international criminal justice journal (CAJ). In the international groupings, Don A. Andrews was the top scholar in one criminology (CJC) and two criminal justice (CJB and IJOT) journals. Interestingly, in the French language Canadian journal CRGE, only 3.3% of authors were American, but the five most-cited scholars were all American.

Table 2 Five most-cited scholars in each journal in 2015
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Table 3 reports the 10 most-cited scholars in each group of journals in 2015 and also compares the consistency of their ranks in previous years (1990, 1995, 2000, 2005, 2010, 2015). In order to rank the scholars and give equal weight to each journal, each scholar was given a score of 51 minus their rank in each journal. Thus, the top-ranked scholar in a journal would score 50, the 50th-ranked scholar would score 1, and all scholars outside the top 50 would score zero. The total scores in five journals are shown in Table 3.

Table 3 Most-cited scholars in groups of five journals in 2015
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In American journals, Sampson remained consistent; since 1990, he has been in the top 10, and since 2000, he has been the most-cited scholar. David P. Farrington, John H. Laub, and Travis Hirschi also displayed similar, though not as highly ranked, rates of consistency over the years. Hirschi also remained consistently influential in the American criminal justice journals, and Francis T. Cullen rose from the top 15 in 1990 and 1995 to be in the top 1 or 2 since the year 2000. Less consistency was evident in either international series; only Cullen was within the top 30, and then the top 10, scholars in international criminal justice journals in all years.

Table 4 combines the journals into groups of 10 to examine the similarities and differences between criminology and criminal justice journals and between American and international journals. In the 10 criminology journals, Sampson, Farrington, and Hirschi all ranked in the top 30 in all years. In the 10 criminal justice journals, Cullen, Sampson, Farrington, and Hirschi were joined by Andrews as the top scholars retaining significant influence over time. In the 10 American journals, Sampson, Cullen, Farrington, and Hirschi remained influential, but Michael R. Gottfredson also emerged as a consistently highly cited scholar. In the 10 international journals, only Sampson, Farrington, and James L. Bonta were ranked in the top 20 since 2000.

Table 4 Ten most-cited scholars in groups of ten journals in 2015
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Table 5 presents the most-cited scholars (all those ranked up to 40 on their total scores) across all 20 journals in 2015 and reports their score across criminology and criminal justice journal groupings. Of the top four, only Alex R. Piquero was new since 2000; the other three (Sampson, Farrington, and Cullen) were highly ranked from 1990 onwards. Outside the top four, only Hirschi and Gottfredson were ranked in the top 40 in every year. The top eight scholars generally scored higher in criminal justice journals, indicating a more significant representation in that field; the sole exception was Sampson, who scored higher in criminology journals.

Table 5 Forty most-cited scholars in all twenty journals in 2015
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Table 6 shows the 50 most-cited scholars in AJC in 2015. The most-cited scholars were Ken Pease, Alex R. Piquero, Rolf Loeber, and John H. Laub. Of the 50 scholars, 33 were American, eight were British, three were Australian, and six were based in an Asian country (two in Japan, two in Hong Kong, one in Taiwan, and one in Macau). Of the 41 most-cited scholars in 20 journals in Table 5, 14 were among the most-cited scholars in AJC, which seems quite a remarkable overlap. Eight of the top 10 in Table 5 were highly cited in AJC, and conversely four of the top 10 in AJC were in Table 5.

Table 6 Most-cited scholars in the Asian Journal of Criminology in 2015
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Table 7 compares the 20 journals in 2015 to a smaller subset of nine journals for which citation data were analyzed across a five-year period (2011–2015). The top five scholars were identical across both groupings, albeit in a slightly different ordering: Sampson, Piquero, Farrington, Cullen, and Laub (with Piquero and Farrington switching places from the one-year to the five-year comparison). Hirschi, Daniel S. Nagin, and Terrie E. Moffitt also appeared in the top 10 rankings across both comparisons.

Table 7 Comparison of 20 journals in 2015 and nine journals in 2011–2015
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Table 8 examines the most-cited works of the most-cited scholars in 2015. Sampson, the top scholar, had his two most-cited works in the two areas of literature for which he is most known: social disorganization (with his 1997 article “Neighborhoods and violent crime”) and life-course criminology (his 1993 text “Crime in the making”), with 53 and 49 cites, respectively. Piquero, on the other hand, was more widely known for his sheer number of works rather than for any single notable work. His two most-cited articles were the 1998 article “Using the correct statistical test for the equality of regression coefficients” (with 16 cites) and the 2011 article “New frontiers in criminal careers research, 2000–2011” (with 12 cites). Of the top 10, Sampson, Piquero, Farrington, Laub, Nagin, Moffitt, and Loeber all tended to be most-cited for their works in developmental and life-course criminology, showing the dominance of this area in contemporary criminology.

Table 8 Most-cited works of the most-cited scholars in 2015
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Table 9 reports the prevalence and frequency of the top scholars in 2015. Sampson, with a total of 536 citations across 297 articles, had an average of 1.80 citations per article. Piquero, ranked 2, had 420 total citations across 171 different articles, and an average of 2.46 citations per article. These numbers suggest that Sampson and Piquero are highly cited primarily because of their quantity of work, rather than for any one particular work. In contrast, Tom R. Tyler, ranked 10, had 191 citations across 47 different articles, and an average of 4.06 citations per article, suggesting that he was more likely to have multiple citations to a smaller number of works.

Table 9 Prevalence and frequency in 2015
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To further address this point, Table 10 examines the specialization and versatility of scholars in 2015. Specialized scholars are those with a relatively small number of cited works and a relatively large number of citations per work, whereas versatile scholars tend to have a relatively large number of cited works and a relatively small number of citations per work. Specialized scholars will tend to have a relatively large fraction of their citations accruing to a small number of works, whereas versatile scholars will tend to have a small fraction of their citations accounted for by their most-cited works. For Sampson, his two most-cited works only accounted for 19% of his citations, while Piquero’s two most-cited works only accounted for 7% of his total number. Sampson and Piquero, therefore, are versatile scholars. Comparatively, for Hirschi, who is best known for his seminal work on causes of crime and the general theory of crime, his most-cited two works accounted for 63% of his citations, making him a specialized scholar. Generally, however, the top scholars tended to be highly cited because of the versatile nature of their work, reflecting their high productivity.

Table 10 Specialization and versatility in 2015
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Conclusion

Across 20 American and international criminology and criminal justice journals in 2015, the most-cited scholars tended to be those who carried out research on developmental and life-course criminology; among the top 9 on our measure were Sampson, Piquero, Farrington, Laub, Nagin, Moffitt, and Loeber. Only Cullen and Hirschi were not clearly developmental and life-course criminology researchers. Furthermore, seven of the top nine scholars were among the most-cited scholars in the majority of previous years studied from 1990 to 2010: Sampson, Farrington, Cullen, Laub, Hirschi, Moffitt, and Loeber. This shows great consistency in the most-cited scholars and therefore the persistence of scholarly influence. Only Piquero and Nagin were relatively recent entries, from 2005 onwards.

The most-cited scholars in 10 criminology journals in 2015 were remarkably similar to the most-cited scholars in 10 criminal justice journals: Sampson, Piquero, Farrington, Laub, Cullen, Hirschi, and Nagin featured in both lists. Five of the top eight scholars in criminology journals were highly ranked in the majority of previous years, and five of the top eight scholars in criminal justice journals were highly ranked in the majority of previous years. The most-cited scholars in 10 American journals in 2015 were remarkably similar to the most-cited scholars in 10 international journals: Sampson, Piquero, Farrington, Cullen, and Laub featured in both lists. Seven of the top nine scholars in American journals were highly ranked in the majority of previous years, but only four of the top nine scholars in international journals were highly ranked in the majority of previous years. Therefore, there was more stability over time of citations in American journals than of citations in international journals.

Remarkably, eight of the most-cited nine scholars in all 20 journals were among the most-cited in AJC: Sampson, Piquero, Farrington, Cullen, Laub, Nagin, Moffitt, and Loeber. This was also true of seven of the top 10 scholars in 10 criminology journals, six of the top 10 scholars in 10 criminal justice journals, eight of the top 10 scholars in 10 American journals, and six of the top 10 scholars in 10 international journals. Therefore, AJC citations generally identify the same highly cited scholars as in other criminology and criminal justice journals.

In conclusion, a large number of American and international criminology and criminal justice journals, as well as AJC, identify the same highly cited scholars, most of whom are highly cited for their work in developmental and life-course criminology. We conclude that there is considerable agreement in American, Asian, and international criminology and criminal justice on the most-cited, and therefore most influential, scholars.