In his presentation at a 2019 chemometrics conference in France, Steven Brown called Kowalski the "father" of the following areas of chemometrics: NAS methods (with K. Booksh), multiway methods (with E. Sanchez), heuristics in chemistry (with C. Bender), multi-algorithms in chemistry for “big data” ( > 16 kb).
Responding to a question posed during a 1988 interview, Kowalski felt that his most impactful paper to date was the one he wrote with C. Bender, published in the Journal of the American Chemical Society in 1972, "Pattern recognition. A Powerful approach to interpreting chemical data". Wold categorized this publication as a "seminal" paper in pattern recognition in chemistry.
Kowalski's areas of interest outside of chemometrics were analytical instrumentation, remote sensing, process modeling, and chemical sensors in process analysis and control.