List of publications by Ludo Waltman

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• Visser, M., Van Eck, N.J., & Waltman, L. (2020). Large-scale comparison of bibliographic data sources: Scopus, Web of Science, Dimensions, Crossref, and Microsoft Academic. arXiv:2005.10732. See also this blog post.
• Colavizza, G., Costas, R., Traag, V.A., Van Eck, N.J., Van Leeuwen, T., & Waltman, L. (2020). A scientometric overview of CORD-19. bioRxiv. See also this blog post.
• Sjögårde, P., Ahlgren, P., & Waltman, L. (2020). Algorithmic labeling in hierarchical classifications of publications: Evaluation of bibliographic fields and term weighting approaches. arXiv:2004.08090.
• Bu, Y., Waltman, L., & Huang, Y. (2019). A multidimensional framework for characterizing the citation impact of scientific publications. arXiv:1901.09663.
• Waltman, L., Boyack, K.W., Colavizza, G., & Van Eck, N.J. (2020). A principled methodology for comparing relatedness measures for clustering publications. Quantitative Science Studies, 1(2), 691-713. arXiv:1901.06815.
• Waltman, L., & Traag, V.A. (2020). Use of the journal impact factor for assessing individual articles need not be statistically wrong. F1000Research, 9, 366. arXiv:1703.02334. See also this blog post.
• Waltman, L., & Larivière, V. (2020). Special issue on bibliographic data sources. Quantitative Science Studies, 1(1), 360-362. Editorial.
• Waltman, L., Larivière, V., Milojevic, S., & Sugimoto, C.R. (2020). Opening science: The rebirth of a scholarly journal. Quantitative Science Studies, 1(1), 1-3. Editorial.
• Subelj, L., Waltman, L., Traag, V.A., & Van Eck, N.J. (2020). Intermediacy of publications. Royal Society Open Science, 7(1), 190207. arXiv:1812.08259.
• Waltman, L., & Van Eck, N.J. (2019). Field normalization of scientometric indicators. In W. Glänzel et al. (Eds.), Handbook of science and technology indicators (pp. 281-300). Springer. arXiv:1801.09985.
• Wouters, P., Sugimoto, C.R., Larivière, V., McVeigh, M.E., Pulverer, B., De Rijcke, S., & Waltman, L. (2019). Rethinking impact factors: Better ways to judge a journal. Nature, 569, 621-623. Comment.
• Traag, V.A., Waltman, L., & Van Eck, N.J. (2019). From Louvain to Leiden: Guaranteeing well-connected communities. Scientific Reports, 9, 5233. arXiv:1810.08473. See also this blog post. The software is available here.
• Traag, V.A. & Waltman, L. (2019). Systematic analysis of agreement between metrics and peer review in the UK REF. Palgrave Communications, 5, 29. arXiv:1808.03491. See also this blog post.
• Van Eck, N.J., & Waltman, L. (2018). Analyzing the activities of visitors of the Leiden Ranking website. Journal of Data and Information Science, 3(3), 81-98. arXiv:1804.03869. See also this blog post. The data is available here.
• Van de Laar, L., De Kruif, T., Waltman, L., Meijer, I., Gupta, A., & Hagenaars, N. (2018). Improving the evaluation of worldwide biomedical research output: Classification method and standardised bibliometric indicators by disease. BMJ Open, 8, e020818.
• Colavizza, G., Boyack, K.W., Van Eck, N.J., & Waltman, L. (2018). The closer the better: Similarity of publication pairs at different co-citation levels. Journal of the Association for Information Science and Technology, 69(4), 600-609. arXiv:1707.03076.
• Fortunato, S., Bergstrom, C.T., Börner, K., Evans, J.A., Helbing, D., Milojević, S., ... Barabási, A.-L. (2018). Science of science. Science, 359, eaao0185.
• Boyack, K.W., Van Eck, N.J., Colavizza, G., & Waltman, L. (2018). Characterizing in-text citations in scientific articles: A large-scale analysis. Journal of Informetrics, 12(1), 59-73. arXiv:1710.03094.
• Waltman, L. (2017). Special section on performance-based research funding systems. Journal of Informetrics, 11(3), 904. Editorial.
• Waltman, L., & Traag, V. (2017). Impact factors: Is the Nature Index at odds with DORA? Nature, 545(7655), 412. Correspondence.
• Van Eck, N.J., & Waltman, L. (2017). Citation-based clustering of publications using CitNetExplorer and VOSviewer. Scientometrics, 111(2), 1053-1070. arXiv:1702.03411.
• Waltman, L. (2016). Conceptual difficulties in the use of statistical inference in citation analysis. Journal of Informetrics, 10(4), 1249-1252. arXiv:1612.03285.
• Waltman, L. (2016). Special section on statistical inference in citation analysis. Journal of Informetrics, 10(4), 1224. Editorial.
• Perianes-Rodriguez, A., Waltman, L., & Van Eck, N.J. (2016). Constructing bibliometric networks: A comparison between full and fractional counting. Journal of Informetrics, 10(4), 1178-1195. arXiv:1607.02452.
• Chorus, C.G., & Waltman, L. (2016). A large-scale analysis of impact factor biased journal self-citations. PLOS ONE, 11(8), e0161021.
• Waltman, L., Van Eck, N.J., Visser, M., & Wouters, P. (2016). The elephant in the room: The problem of quantifying productivity in evaluative scientometrics. Journal of Informetrics, 10(2), 671-674. arXiv:1605.02378.
• Waltman, L. (2016). Special section on size-independent indicators in citation analysis. Journal of Informetrics, 10(2), 645. Editorial.
• Subelj, L., Van Eck, N.J., & Waltman, L. (2016). Clustering scientific publications based on citation relations: A systematic comparison of different methods. PLOS ONE, 11(4), e0154404. arXiv:1512.09023.
• Waltman, L. (2016). A review of the literature on citation impact indicators. Journal of Informetrics, 10(2), 365-391. arXiv:1507.02099.
• Wang, Q., & Waltman, L. (2016). Large-scale analysis of the accuracy of the journal classification systems of Web of Science and Scopus. Journal of Informetrics, 10(2), 347-364. arXiv:1511.00735. Some supplementary material is available here.
• De Groot, C.J.M., Van Leeuwen, T., Mol, B.W.J., & Waltman, L. (2015). A longitudinal analysis of publications on maternal mortality. Paediatric and Perinatal Epidemiology, 29(6), 481-489.
• Waltman, L., & Van Eck, N.J. (2015). Field-normalized citation impact indicators and the choice of an appropriate counting method. Journal of Informetrics, 9(4), 872-894. arXiv:1501.04431. Some supplementary material is available here.
• Stegehuis, C., Litvak, N., & Waltman, L. (2015). Predicting the long-term citation impact of recent publications. Journal of Informetrics, 9(3), 642-657. arXiv:1503.09156.
• Hicks, D., Wouters, P., Waltman, L., De Rijcke, S., & Rafols, I. (2015). The Leiden Manifesto for research metrics. Nature, 520, 429-431. Comment.
• Ruiz-Castillo, J., & Waltman, L. (2015). Field-normalized citation impact indicators using algorithmically constructed classification systems of science. Journal of Informetrics, 9(1), 102-117.
• Waltman, L. (2015). Message from the new Editor-in-Chief. Journal of Informetrics, 9(1), A3-A6. Editorial.
• Van Eck, N.J., & Waltman, L. (2014). Visualizing bibliometric networks. In Y. Ding, R. Rousseau, & D. Wolfram (Eds.), Measuring scholarly impact: Methods and practice (pp. 285-320). Springer.
• Waltman, L., & Yan, E. (2014). PageRank-related methods for analyzing citation networks. In Y. Ding, R. Rousseau, & D. Wolfram (Eds.), Measuring scholarly impact: Methods and practice (pp. 83-100). Springer.
• Waltman, L., Van Raan, A.F.J., & Smart, S. (2014). Exploring the relationship between the Engineering and Physical Sciences and the Health and Life Sciences by advanced bibliometric methods. PLOS ONE, 9(10), e111530. arXiv:1407.0199. Some supplementary material is available here.
• Ahlgren, P., & Waltman, L. (2014). The correlation between citation-based and expert-based assessments of publication channels: SNIP and SJR vs. Norwegian quality assessments. Journal of Informetrics, 8(4), 985-996.
• Van Eck, N.J., & Waltman, L. (2014). CitNetExplorer: A new software tool for analyzing and visualizing citation networks. Journal of Informetrics, 8(4), 802-823. arXiv:1404.5322.
• Rodrigues, S.P., Van Eck, N.J., Waltman, L., & Jansen, F.W. (2014). Mapping patient safety: A large-scale literature review using bibliometric visualization techniques. BMJ Open, 4(3), e004468.
• Waltman, L., & Costas, R. (2014). F1000 recommendations as a potential new data source for research evaluation: A comparison with citations. Journal of the Association for Information Science and Technology, 65(3), 433-445. arXiv:1303.3875.
• Waltman, L., & Van Eck, N.J. (2013). A smart local moving algorithm for large-scale modularity-based community detection. European Physical Journal B, 86(11), 471. arXiv:1308.6604. The software is available here.
• Waltman, L., Van Eck, N.J., Dekker, R., & Kaymak, U. (2013). An evolutionary model of price competition among spatially distributed firms. Computational Economics, 42(4), 373-391. The software is available here.
• Waltman, L., & Van Eck, N.J. (2013). A systematic empirical comparison of different approaches for normalizing citation impact indicators. Journal of Informetrics, 7(4), 833-849. arXiv:1301.4941. Some supplementary material is available here.
• Waltman, L., & Van Eck, N.J. (2013). Source normalized indicators of citation impact: An overview of different approaches and an empirical comparison. Scientometrics, 96(3), 699-716. arXiv:1208.6122. Some supplementary material is available here.
• Waltman, L., Van Eck, N.J., & Wouters, P. (2013). Counting publications and citations: Is more always better? Journal of Informetrics, 7(3), 635-641. arXiv:1301.4597.
• Van Eck, N.J., Waltman, L., Van Raan, A.F.J., Klautz, R.J.M., & Peul, W.C. (2013). Citation analysis may severely underestimate the impact of clinical research as compared to basic research. PLoS ONE, 8(4), e62395. arXiv:1210.0442. Some supplementary material is available here.
• Waltman, L., & Schreiber, M. (2013). On the calculation of percentile-based bibliometric indicators. Journal of the American Society for Information Science and Technology, 64(2), 372-379. arXiv:1205.0646.
• Waltman, L., Van Eck, N.J., Van Leeuwen, T.N., & Visser, M.S. (2013). Some modifications to the SNIP journal impact indicator. Journal of Informetrics, 7(2), 272-285. arXiv:1209.0785.
• Waltman, L., & Van Eck, N.J. (2012). A new methodology for constructing a publication-level classification system of science. Journal of the American Society for Information Science and Technology, 63(12), 2378-2392. arXiv:1203.0532. Some supplementary material is available here.
• Waltman, L., Calero-Medina, C., Kosten, J., Noyons, E.C.M., Tijssen, R.J.W., Van Eck, N.J., ... Wouters, P. (2012). The Leiden Ranking 2011/2012: Data collection, indicators, and interpretation. Journal of the American Society for Information Science and Technology, 63(12), 2419-2432. arXiv:1202.3941. The Leiden Ranking 2011/2012 is available here.
• Waltman, L., Costas, R., & Van Eck, N.J. (2012). Some limitations of the h-index: A commentary on Ruscio and colleagues' analysis of bibliometric indices. Measurement: Interdisciplinary Research and Perspectives, 10(3), 172-175.
• Waltman, L. (2012). An empirical analysis of the use of alphabetical authorship in scientific publishing. Journal of Informetrics, 6(4), 700-711. arXiv:1206.4863. Some supplementary material is available here.
• Waltman, L., & Van Eck, N.J. (2012). A mathematical analysis of the long-run behavior of genetic algorithms for social modeling. Soft Computing, 16(6), 1071-1089. The software is available here.
• Waltman, L., & Van Eck, N.J. (2012). The inconsistency of the h-index. Journal of the American Society for Information Science and Technology, 63(2), 406-415. arXiv:1108.3901.
• Waltman, L., Van Eck, N.J., & Van Raan, A.F.J. (2012). Universality of citation distributions revisited. Journal of the American Society for Information Science and Technology, 63(1), 72-77. arXiv:1105.2934.
• Waltman, L., Van Eck, N.J., Dekker, R., & Kaymak, U. (2011). Economic modeling using evolutionary algorithms: The effect of a binary encoding of strategies. Journal of Evolutionary Economics, 21(5), 737-756. The software is available here.
• Waltman, L., Tijssen, R.J.W., & Van Eck, N.J. (2011). Globalisation of science in kilometres. Journal of Informetrics, 5(4), 574-582. arXiv:1103.3648.
• Bornmann, L., & Waltman, L. (2011). The detection of "hot regions" in the geography of science: A visualization approach by using density maps. Journal of Informetrics, 5(4), 547-553. arXiv:1102.3862. Some supplementary material is available here.
• Waltman, L., Yan, E., & Van Eck, N.J. (2011). A recursive field-normalized bibliometric performance indicator: An application to the field of library and information science. Scientometrics, 89(1), 301-314. arXiv:1105.3212.
• Waltman, L., Van Eck, N.J., Van Leeuwen, T.N., Visser, M.S., & Van Raan, A.F.J. (2011). On the correlation between bibliometric indicators and peer review: Reply to Opthof and Leydesdorff. Scientometrics, 88(3), 1017-1022. arXiv:1105.5316. The data is available here.
• Tijssen, R.J.W., Waltman, L., & Van Eck, N.J. (2011). Collaborations span 1,553 kilometres. Nature, 473(7346), 154. Correspondence.
• Waltman, L., Van Eck, N.J., Van Leeuwen, T.N., Visser, M.S., & Van Raan, A.F.J. (2011). Towards a new crown indicator: An empirical analysis. Scientometrics, 87(3), 467-481. arXiv:1004.1632.
• Egghe, L., & Waltman, L. (2011). Relations between the shape of a size-frequency distribution and the shape of a rank-frequency distribution. Information Processing and Management, 47(2), 238-245.
• Waltman, L., Van Eck, N.J., Van Leeuwen, T.N., Visser, M.S., & Van Raan, A.F.J. (2011). Towards a new crown indicator: Some theoretical considerations. Journal of Informetrics, 5(1), 37-47. arXiv:1003.2167.
• Van Eck, N.J., & Waltman, L. (2011). Text mining and visualization using VOSviewer. ISSI Newsletter, 7(3), 50-54. arXiv:1109.2058. The term maps are available here.
• Van Eck, N.J., Waltman, L., Dekker, R., & Van den Berg, J. (2010). A comparison of two techniques for bibliometric mapping: Multidimensional scaling and VOS. Journal of the American Society for Information Science and Technology, 61(12), 2405-2416. arXiv:1003.2551. The bibliometric maps are available here.
• Waltman, L., Van Eck, N.J., & Noyons, E.C.M. (2010). A unified approach to mapping and clustering of bibliometric networks. Journal of Informetrics, 4(4), 629-635. arXiv:1006.1032. Some supplementary material is available here.
• Waltman, L., & Van Eck, N.J. (2010). The relation between Eigenfactor, audience factor, and influence weight. Journal of the American Society for Information Science and Technology, 61(7), 1476-1486. arXiv:1003.2198.
• Van Eck, N.J., & Waltman, L. (2010). Software survey: VOSviewer, a computer program for bibliometric mapping. Scientometrics, 84(2), 523-538. VOSviewer is available here. The journal co-citation map is available here.
• Van Raan, A.F.J., Van Leeuwen, T.N., Visser, M.S., Van Eck, N.J., & Waltman, L. (2010). Rivals for the crown: Reply to Opthof and Leydesdorff. Journal of Informetrics, 4(3), 431-435. arXiv:1003.2113.
• Van Eck, N.J., Waltman, L., Noyons, E.C.M., & Buter, R.K. (2010). Automatic term identification for bibliometric mapping. Scientometrics, 82(3), 581-596. The term map is available here.
• Van Eck, N.J., & Waltman, L. (2009). On the proper understanding of the limiting behavior of generalizations of the h- and g-indices. Journal of Informetrics, 3(4), 369-370. Letter to the editor.
• Waltman, L., & Van Eck, N.J. (2009). Some comments on Egghe's derivation of the impact factor distribution. Journal of Informetrics, 3(4), 363-366.
• Van Eck, N.J., & Waltman, L. (2009). How to normalize cooccurrence data? An analysis of some well-known similarity measures. Journal of the American Society for Information Science and Technology, 60(8), 1635-1651.
• Waltman, L., & Van Eck, N.J. (2009). Robust evolutionary algorithm design for socio-economic simulation: Some comments. Computational Economics, 33(1), 103-105.
• Waltman, L., & Van Eck, N.J. (2009). A simple alternative to the h-index. ISSI Newsletter, 5(3), 46-48.
• Waltman, L., & Van Eck, N.J. (2008). Some comments on the journal weighted impact factor proposed by Habibzadeh and Yadollahie. Journal of Informetrics, 2(4), 369-372.
• Van Eck, N.J., & Waltman, L. (2008). Generalizing the h- and g-indices. Journal of Informetrics, 2(4), 263-271.
• Waltman, L., & Kaymak, U. (2008). Q-learning agents in a Cournot oligopoly model. Journal of Economic Dynamics and Control, 32(10), 3275-3293. The source code of the simulations is available here.
• Van Eck, N.J., & Waltman, L. (2008). Appropriate similarity measures for author cocitation analysis. Journal of the American Society for Information Science and Technology, 59(10), 1653-1661.
• Van Eck, N.J., & Waltman, L. (2007). Bibliometric mapping of the computational intelligence field. International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems, 15(5), 625-645. The concept (density) maps and the concept map viewer are available here.
• Waltman, L., & Van Eck, N.J. (2007). Some comments on the question whether co-occurrence data should be normalized. Journal of the American Society for Information Science and Technology, 58(11), 1701-1703.
• Van Eck, N.J., Waltman, L., Van den Berg, J., & Kaymak, U. (2006). Visualizing the computational intelligence field. IEEE Computational Intelligence Magazine, 1(4), 6-10. The concept map viewer is available here.