Bruce R. Kowalski: The Maverick Mind Behind Chemometrics

Bruce R. Kowalski (1942–2012) is widely regarded as a founding figure in the field of chemometrics. His pioneering work in multivariate statistics, pattern recognition, and data processing enabled chemists to interpret complex chemical data more effectively and reproducibly. This article honors Kowalski’s life and career, highlighting his foundational role in the development of chemometric theory, the establishment of educational programs and research centers, and the co-founding of the Journal of Chemometrics. His influence extended globally through academic mentorship, practical software applications, and enduring leadership within the analytical chemistry community. Through this retrospective, we reflect on Kowalski’s legacy and the continuing relevance of his contributions to science.

Origins of a Visionary

Bruce R. Kowalski was born in March 1942 and passed away in December 2012, leaving behind an immense legacy in analytical chemistry. From his earliest days, Kowalski’s academic and intellectual talents revealed a deep commitment to crossing disciplinary boundaries. As an undergraduate at Millikin University, he double-majored in chemistry and mathematics—an unusual combination at the time that prefigured his life’s work. That early integration of chemical intuition with mathematical logic would later become the defining feature of a new scientific discipline: chemometrics (1,2).

Bruce R. Kowalski

Kowalski earned his Ph.D. in chemistry at the University of Washington in 1969 under the mentorship of Tom Isenhour. After a brief stint in industrial research at Shell Development, he transitioned to the Lawrence Livermore Laboratory, where he worked with scientist Charles F. Bender. There, the seeds of chemometrics were quietly taking root, nourished by their collaboration on PATTRN, an early proprietary system for pattern recognition in chemical data (1).

Forging a Discipline

It was in the 1970s that Kowalski began shaping chemometrics into a formalized field. In 1975, he published a landmark paper, "Chemometrics: Views and Propositions," which offered one of the earliest comprehensive definitions of the field. In the paper, he defined chemometrics as “any and all methods that can be used to extract useful chemical information from raw data” (2). This wasn’t just a new vocabulary—it was a paradigm shift. At a time when analytical chemistry largely focused on instrumentation and wet chemistry, Kowalski’s proposal that statistical modeling and data interpretation were equally vital was radical for its time.

His collaboration with Swedish chemometrician Svante Wold was pivotal. Wold had coined the term “chemometrics” in a grant proposal in 1971 (3,4), but it was his meeting with Kowalski in Tucson in 1973 that ignited a transatlantic partnership. On June 10, 1974, the pair launched the informal Chemometrics Society, which would eventually evolve into the International Chemometrics Society (2,5). Their joint statement to “prospective chemometricians” emphasized that the field should prioritize real-world data interpretation over theoretical abstraction (5,6). It was a declaration of practical scientific utility that resonated across academia and industry alike.

The Chemometrics Society and International Legacy

Under Kowalski and Wold's guidance, the nascent Chemometrics Society served as a beacon for researchers interested in combining chemistry with mathematics and statistics. It provided a community for chemists who felt isolated in their efforts to innovate through computational and data-driven techniques.

Kowalski’s natural charisma and penchant for networking allowed this society to flourish. He had a well-known knack for finding, encouraging, and promoting talent. His ability to recognize promise in his students and collaborators would shape multiple generations of trained chemometrics scientists. He understood that you live on through your students, and he never failed to promote them, saying something nice about them to others (2).

In 1987, Kowalski became the founding editor of the Journal of Chemometrics. This was more than a publication—it was a rallying point. In the first editorial, Kowalski and his co-editors noted that although chemometric techniques had been employed for two decades, they had been “widely distributed through the literature.” The journal provided a consolidated forum for innovation, application, and theoretical development (1,6).

In 1986, Kowalski co-authored the first book having the title “Chemometrics,” with Sharaf and Illman (7).

In 1994, the Journal of Chemometrics honored Kowalski’s memory with a special issue and an annual award—the Kowalski Prize, celebrating outstanding theoretical or applied papers. This recognition is an enduring testament to his central place in the field (8).

The University Years: Mentorship and Impact

Kowalski joined the chemistry faculty at Colorado State University in 1972, before moving permanently to the University of Washington in 1974. He became a full professor in 1979 and was named Endowed Professor of Analytical Chemistry in 1991—a position created through a consortium of industry and state funding, underscoring the bridge he built between academia and the private sector (1).

Throughout his academic career, he advised 32 Ph.D. students and three master's students. His graduate students have since populated the worlds of academia, industry, and government research, carrying forward his principles of rigorous, application-focused science. With over 230 publications, 144 coauthors, and four patents, Kowalski’s scientific footprint was immense. But it was his mentorship that left an arguably greater impact (1).

As former student David Duewer summarized, “Kowalski wasn’t just a prolific scientist; he was a mentor who changed lives. His enthusiasm was contagious, his intellectual curiosity boundless, and his support unwavering. He was known to amplify the voices of those around him, spreading credit generously and nurturing a collaborative spirit” (1).

The Founding of CPAC: Academia Meets Industry

Kowalski was not content to keep chemometrics confined to academic circles. In 1984, he became the founding director of the Center for Process Analytical Chemistry (CPAC) at the University of Washington along with Jim Callis. Initially launched as a National Science Foundation Industry-University Cooperative Research Center (IUCRC), CPAC quickly became a global model of interdisciplinary collaboration (9).

Alan Newman of Analytical Chemistry described CPAC as Kowalski’s “brainchild.” It enabled cross-pollination between academic chemists, industrial scientists, and government agencies, promoting technologies that could directly influence process monitoring, quality assurance, and real-time chemical analysis. CPAC remains a symbol of Kowalski’s unique ability to align scientific creativity with practical impact (9).

Publications and Research: A Legacy in Print

Kowalski's research touched many of the core pillars of chemometric theory and practice. His work with C.F. Bender on pattern recognition, especially their 1972 paper “Pattern recognition. A powerful approach to interpreting chemical data” in Journal of the American Chemical Society, was considered by Wold to be a seminal contribution to analytical chemistry (10).

In 1978 Kowalski wrote a review paper titled “Chemometrics” published in Analytical Letters (11) This paper catalyzed the multi-year Fundamental Reviews series titled “Chemometrics” published in Analytical Chemistry from 1980 until 2012. Kowalski established this series by co-authoring three of the first four reviews (12–14). A complete listing of the Analytical Chemistry Fundamental Reviews in Chemometrics is given in reference (15).

Kowalski’s later research collaborations explored net analyte signal (NAS) methods with Karl Booksh, Avraham Lorber, and Klaas Faber (16,17). The net analyte signal (NAS) represents the portion of a measured signal that is uniquely attributable to the analyte of interest, excluding contributions from other interfering components. It plays a critical role in evaluating calibration models by enabling the calculation of key figures of merit such as selectivity and sensitivity. Traditionally, NAS has only been computed using direct calibration models, which require full knowledge of all pure component spectra or concentrations. However, recent advancements demonstrate that NAS can also be calculated using inverse calibration models, which do not require complete information about interferents. This broadens the applicability of NAS, particularly in practical scenarios like determining protein content in wheat using near-infrared spectroscopy, where interferent information may be incomplete (17).

Multiway analysis research, including tensorial calibration and direct trilinear decomposition was explored and published with Eugenio Sanchez (18–20). Direct Trilinear Decomposition (DTLD) and Tensorial Calibration are both multi-way chemometric methods used to analyze and model complex data with three or more dimensions. DTLD breaks down multi-dimensional data, such as sample × wavelength × time matrices, into simpler trilinear components without losing the natural structure of the data, making it especially useful for interpreting spectroscopic and time-resolved measurements. Tensorial Calibration, on the other hand, focuses on building predictive models from multi-way data by extending traditional calibration approaches like PLS to work directly with tensor-structured inputs. Both methods preserve and utilize the full dimensionality of the data, allowing for more accurate and interpretable results in fields like spectroscopy, chemical analysis, and process monitoring. Second-order calibration, enabled by multi-way (multi-dimensional) analytical methods, allows for the selective rejection of interferents not present in the original calibration set. This represents a significant advancement in calibration robustness and generalization capability.

A set of comprehensive reviews of the application of chemometrics to spectroscopy, including multiway methods, was published as a comprehensive three–part series in Applied Spectroscopy Reviews (21–23).

Kowalski contributed applications of algorithmic approaches for large-scale data interpretation—what might today be called “big data” analytics (5) as well as described the design of an expert calibration system for spectroscopic based process analytical chemistry (24). These efforts helped lay the groundwork for later developments in machine learning and artificial intelligence (AI) in chemical sciences.

Kowalski co-founded Infometrix in 1978 with Gerald Erickson, a chemometrics software company that helped bring advanced data analysis tools directly to practicing chemists (25). This entrepreneurial venture reflected Kowalski’s enduring belief that science must be translated into practical and understandable tools that people can readily use.

The work of Kowalski and his students using MATLAB laid the groundwork for Barry Wise and Neal Gallagher to create Eigenvector Research, Inc., on January 1, 1995, which is now a leading chemometrics software development, consulting and training company (26).

Life Outside the Lab

Kowalski’s vibrancy extended well beyond academic walls. He was known for his flamboyant personality—riding his Harley-Davidson, sailing the Pacific, hiking wilderness trails, or skiing mountain slopes. He was a horse breeder, a backpacker, and an adventurer (27).

After retiring in 1999, he moved to Durango, Colorado, where he joined the Fort Lewis Mesa Fire Department. Specializing in hazardous materials, Kowalski also became involved in canine search and rescue, working alongside his companion dog, Chaco-Bob. These efforts were among his proudest achievements—a scientist turned rescuer, still using data and logic to save lives, but now under very different conditions (28).

Honors, Awards, and Enduring Influence

Table I: Kowalski received numerous honors over his career, including the following (27,29).

In his memory, the University of Washington established three scholarship funds in his name. The Society for Applied Spectroscopy administers the Bruce R. Kowalski Award in Chemometrics, recognizing emerging talents in mathematical and statistical methods in chemistry (29). The American Chemical Society hosted a symposium in 2015 entitled “40 Years of Chemometrics–From Bruce Kowalski to the Future,” a fitting tribute to his far-reaching influence (30). It was reported over the years that Kowalski’s list of awards could have been longer, but he started turning them down, telling award committees to choose a younger person, earlier in their career, whom the award might benefit more.

Epilogue: An Irreplaceable Presence

Kowalski was more than a founder of a discipline. He was its ambassador, philosopher, and mentor-in-chief. His ability to synthesize disparate ideas, his unflagging belief in the power of names and ideas, and his generosity of spirit transformed chemometrics from a niche curiosity into a foundational pillar of modern analytical chemistry.

Kowalski actively collaborated across disciplines, notably with N. L. Ricker in the University of Washington’s Chemical Engineering department. This interdisciplinary work produced some of the earliest publications applying chemometric methods—specifically principal component models—to chemical process monitoring (31).

As one colleague noted after his passing: “The full breadth of Kowalski’s influence is really too big to capture… The ‘Kowalski Web’ in chemometrics still places him at the center” (2).

In the end, Kowalski exemplified what it means to be a scientist: endlessly curious, rigorously critical, daringly innovative—and always human.

He will be missed, but his vision continues to shape the future.

Acknowledgments: Appreciation to Barry M. Wise, President of Eigenvector Research, Inc. in Manson, WA; and Brian Rohrback, President of Infometrix, Inc. in Bothell, WA, for review and comments on this article.

References

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(2) Barry Wise Tribute Page to Bruce Kowalski, December 3, 2012. Available at: https://eigenvector.com/bruce-kowalski/ (accessed 2025-05-19). Note: According to Barry Wise the June 10, 1974, meeting was “at Casa Lupita Restaurant on Eastlake in Seattle over tacos and margaritas” (Communication on May 23, 2025).

(3) Wold, S. Chemometrics; What Do We Mean With It, and What Do We Want From It? Chemom. Intell. Lab. Syst. 1995, 30 (1), 109–115. DOI: https://doi.org/10.1016/0169-7439(95)00042-9

(4) Wold, S. Chemometrics and Bruce: Some Fond Memories. In 40 Years of Chemometrics–From Bruce Kowalski to the Future; Lavine, B. K., Ed.; ACS Symposium Series 1199; American Chemical Society: Washington, DC, 2015; pp 1–13. DOI: https://doi.org/10.1021/bk-2015-1199.ch001

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(6) Kowalski, B.; Brown, S.; Vandeginste, B. Editorial. J. Chemom. 1987, 1 (1), 1–2. DOI: https://doi.org/10.1002/cem.1180010102

(7) Sharaf, M. A.; Illman, D. L.; Kowalski, B. R. Chemometrics; John Wiley & Sons: New York, 1986.

(8) Journal of Chemometrics Kowalski Prize Page. https://analyticalsciencejournals.onlinelibrary.wiley.com/hub/journal/1099128x/homepage/kowalski_prize.htm (accessed 2025-05-19).

(9) Newman, A. The Center for Process Analytical Chemistry. Anal. Chem.1990, 62 (18), 965A–967A. DOI: https://doi.org/10.1021/ac00217a721

(10) Kowalski, B. R.; Bender, C. F. Pattern Recognition. Powerful Approach to Interpreting Chemical Data. J. Am. Chem. Soc.1972, 94 (16), 5632–5639. DOI: https://doi.org/10.1021/ja00771a016

(11) Kowalski, B. R. Chemometrics. Anal. Lett. 1978, 11 (10), xi–xiii. DOI: https://doi.org/10.1080/00032717808059728

(12) Kowalski, B. R. Chemometrics. Anal. Chem. 1980, 52 (5), 112–122. DOI: https://doi.org/10.1021/ac50055a016

(13) Frank, I. E.; Kowalski, B. R. Chemometrics. Anal. Chem. 1982, 54 (5), 232–243. DOI: https://doi.org/10.1021/ac00242a023

(14) Ramos, L. S.; Beebe, K. R.; Carey, W. P.; Sanchez, E.; Erickson, B. C.; Wilson, B. E.; Wangen, L. E.; Kowalski, B. R. Chemometrics. Anal. Chem.1986, 58 (5), 294–315. DOI: https://doi.org/10.1021/ac00296a020

(15) Workman, J., Jr.; Mark, H. From Classical Regression to AI and Beyond: The Chronicles of Calibration in Spectroscopy: Part I. Spectroscopy 2025, 40 (2), 13–18. DOI: https://doi.org/10.56530/spectroscopy.pu3090t7

(16) Booksh, K. S.; Kowalski, B. R. Theory of Analytical Chemistry. Anal. Chem. 1994, 66, 782A. DOI: https://doi.org/10.1021/ac00087a001

(17) Lorber, A.; Faber, K.; Kowalski, B. R. Net Analyte Signal Calculation in Multivariate Calibration. Anal. Chem. 1997, 69 (8), 1620–1626. DOI: https://doi.org/10.1021/ac960862b

(18) Sanchez, E.; Kowalski, B. R. Tensorial Calibration: I. First‐Order Calibration. J. Chemom. 1988, 2 (4), 247–263. DOI: https://doi.org/10.1002/cem.1180020404

(19) Sanchez, E.; Kowalski, B. R. Tensorial Calibration: II. Second‐Order Calibration. J. Chemom. 1988, 2 (4), 265–280. DOI: https://doi.org/10.1002/cem.1180020405

(20) Sanchez, E.; Kowalski, B. R. Tensorial Resolution: A Direct Trilinear Decomposition. J. Chemom. 1990, 4 (1), 29–45. DOI: https://doi.org/10.1002/cem.1180040105

(21) Workman, J., Jr.; Mobley, P. R.; Kowalski, B. R.; Bro, R. Review of Chemometrics Applied to Spectroscopy: 1985–95, Part I. Appl. Spectrosc. Rev. 1996, 31 (1–2), 73–124. DOI: https://doi.org/10.1080/05704929608000565

(22) Mobley, P. R.; Kowalski, B. R.; Workman, J., Jr.; Bro, R. Review of Chemometrics Applied to Spectroscopy: 1985–95, Part II. Appl. Spectrosc. Rev. 1996, 31 (4), 347–368. DOI: https://doi.org/10.1080/05704929608000575

(23) Bro, R.; Workman, J., Jr.; Mobley, P. R.; Kowalski, B. R. Review of Chemometrics Applied to Spectroscopy: 1985–95, Part III—Multi-Way Analysis. Appl. Spectrosc. Rev. 1997, 32 (3), 237–261. DOI: https://doi.org/10.1080/05704929708003315

(24) Workman, J.; Kowalski, B.; Mobley, P. The Design of an Expert Calibration System for Spectroscopic Based Process Analytical Chemistry. In Proc. Instrument Society of America (ISA) Conference, Toronto, Canada, 1995, April, 97–106. Available from ResearchGate.

(25) Analytically Speaking Podcast, Episode 33: Automating Multivariate Calibrations. https://www.spectroscopyonline.com/view/ep-33-automating-multivariate-calibrations-chronicling-the-steps-for-replacing-the-human-brain-in-most-calibration-situations (accessed 2025-05-19).

(26) Analytically Speaking Podcast, Episode 31: Clarifying the Meaning of Chemometrics, AI, ML, and NNs. https://www.spectroscopyonline.com/view/ep-31-clarifying-the-meaning-of-chemometrics-artificial-intelligence-ai-machine-learning-ml-and-neural-networks-nns (accessed 2025-05-19).

(27) Ainsworth, S. J. Bruce R. Kowalski. Chem. Eng. News 2013, 91 (10), March 11. https://cen.acs.org/articles/91/i10/Bruce-R-Kowalski.html (accessed 2025-05-19).

(28) Bruce R. Kowalski Obituary Page.https://www.hoodmortuary.com/obituaries/kowalski-bruce (accessed 2025-05-19).

(29) Bruce R. Kowalski Wikipedia Page. https://en.wikipedia.org/wiki/Bruce_R._Kowalski (accessed 2025-05-19).

(30) Lavine, B. K., et al., Eds. 40 Years of Chemometrics: From Bruce Kowalski to the Future; ACS Symposium Series 1199; American Chemical Society: Washington, DC, 2015. DOI: https://doi.org/10.1021/bk-2015-1199

(31) Wise, B. M.; Ricker, N. L.; Veltkamp, D. F.; Kowalski, B. R. A Theoretical Basis for the Use of Principal Component Models for Monitoring Multivariate Processes. Process Control Qual.1990, 1 (1), 41–51. https://eigenvector.com/Docs/PCA_Monitoring_Theoretical_Basis.pdf (accessed 2025-05-23).

Additional Resources

(32) Bruce Kowalski ResearchGate Page. Available at: https://www.researchgate.net/scientific-contributions/Bruce-R-Kowalski-79270990 (accessed 2025-05-19).

(33) Bruce Kowalski, The Father of Chemometrics YouTube Page. Available at: https://www.youtube.com/watch?v=qgm1wEAhTKw (accessed 2025-05-19).

(34) Bruce Kowalski Google Scholar Search Page. Available at: https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=bruce+kowalski+chemometrics&oq=Bruce+Kowalski (accessed 2025-05-19).

About the Author

Jerome Workman, Jr. serves on the Editorial Advisory Board of Spectroscopy and is the Executive Editor for LCGC and Spectroscopy. He is the co-host of the Analytically Speaking podcast and has published multiple reference text volumes, including the three-volume Academic Press Handbook of Organic Compounds, the five-volume The Concise Handbook of Analytical Spectroscopy, the 2nd edition of Practical Guide and Spectral Atlas for Interpretive Near-Infrared Spectroscopy, the 2nd edition of Chemometrics in Spectroscopy, and the 4th edition of The Handbook of Near-Infrared Analysis. He is the recipient of the 2020 NYSAS Gold Medal Award (with Howard L. Mark). Author contact:JWorkman@MJHlifesciences.com●